Yahoo Mail IMAP Error Messages

Can anyone explain why I get these error messages in em-Client/8.2 when connected to Yahoo Mail? I don’t get all of them at the same time. It varies. I can still send/receive email from this particular account.

[IMAP]Failed to LIST server folders ( LIST Invalid credentials)
[IMAP]Cannot open folder “/Archive”. (NO [AUTHENTICATIONFAILED] SELECT Invalid credentials)
[IMAP]Cannot open folder “/Trash”. (NO [AUTHENTICATIONFAILED] SELECT Invalid credentials)
[IMAP]Cannot open folder “/Junk E-mail”. (NO [AUTHENTICATIONFAILED] SELECT Invalid credentials)

I have another email account that I have with Yahoo Mail that never gives me any errors. This is my primary email address.

I would appreciate an comments you might have…


Have you given thought to removing that account and re-adding it back to eMC?

I did give it some thought but wasn’t sure it it would fix the problem. The settings for both accounts are the same except for the email address. But since you mentioned it, I guess it’s worth a try.

thank you

I would have a look at this Yahoo IMAP thread in eM Client as yes agree with @sunriseal you need to remove and re add either by the updated eM Client automatic Yahoo setup or the Manual Yahoo options as per explained on the thread below.

Note:- This was all previously fixed and updated in the eM Clients for Yahoo.

Can’t add Yahoo account - Initial setup - eM Client

I deleted the Yahoo Mail Account that is giving me trouble and added a new account using the Auto feature. I still had a couple of the errors I listed in my original email. I then deleted the account again and tried to do a manual set up but it doesn’t ask me for a Port # or Security Policy (SSL/TLS). I read the article that was in the link from Cyberzork and entered the same IMAP and SMTP host. It doesn’t asked for my Yahoo email address and Password, but fails to log in. When I try to do the “Fix” option, it doesn’t have any luck fixing the connection.

When attempting the manual set up, I click on Menu > Accounts > Add Account > Mail > Other > Next.


I started today having exactly same problem. Times 5, that is: I have five Yahoo accounts, which worked fine earlier with eM Client. Not anymore. :frowning_face:

Why AGAIN a Yahoo problem with the great eM Client? So VERY tiring. :face_with_symbols_over_mouth: :rage:

Windows 10, eMail Client Pro 9.0.1708.

To repeatedly do things like what the kind suggestion “removing that account and re-adding it back to eMC” above says is part of the TIRING waste of time we encounter again and again. Can these Yahoo problems EVER be solved “permanently”? We would like to just ENJOY the fantastic eM Client and our own email, NOT fight these continuous problems. P-L-E-A-S-E.

I started today having exactly same problem. Times 5, that is: I have five Yahoo accounts, which worked fine earlier with eM Client. Not anymore.

This error is a Yahoo mail server type error and you need to contact their technical support.

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Thank you so much, cyberzork. Appreciated. :slight_smile:

Once again we see that the best thing to do is NEVER use Yahoo email. For example Outlook and Gmail always work fine with eM Client and “standalone”. Yahoo Email is a relic that should be removed from the earth for good.

Thanks. :slight_smile:

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Unfortunately it’s well known that EmClient encounters problems with the integration of yahoo account :roll_eyes:

This is not an eM Client issue, but a problem with the Yahoo! server. Please contact your email provider as their server is broken.


Is it possible to simply not to display or hide the error ? An option somewhere in Em Client ?
I mean, despite the error log everything works fine and when I click to ignore, next time this reappears again… it’s a never ending story !
Maybe the easy way it’s just not to display the error :wink:

17:34:31 IMAP Synchronisation de la liste des dossiers
17:34:40 [IMAP] MailClient.Protocols.Imap.ImapException: Failed to LIST server folders ( LIST Invalid credentials)
at MailClient.Protocols.Imap.ImapFolderSynchronizer.ListFoldersAsync(IListFoldersProgress progress, Folder homeFolder, CancellationToken cancellationToken)
at MailClient.Protocols.Imap.ImapFolderSynchronizer.ListFoldersAsync(IListFoldersProgress progress, Folder homeFolder, CancellationToken cancellationToken)
at MailClient.Protocols.Imap.ImapFolderSynchronizer.GetFolderList(IListFoldersProgress progress, Folder homeFolder, CancellationToken cancellationToken)
at MailClient.Protocols.Common.FolderSynchronizer.<>c__DisplayClass14_1.b__0(WorkerStatus status, CancellationToken cancellationToken)
at MailClient.Protocols.Imap.ImapActionCommand.<>c__DisplayClass13_0.<.ctor>b__0(WorkerStatus ws, CancellationToken ct)
at MailClient.Protocols.Imap.ImapActionCommand.ExecuteInternalSync(WorkerStatus status)
at MailClient.Protocols.Imap.ImapActionCommand.Execute(WorkerStatus status)
at MailClient.Commands.Command.Process(WorkerStatus status)
— End of stack trace from previous location —
at MailClient.Storage.Synchronization.FolderSynchronizerExtensions.SynchronizeSubfoldersAsync(IFolderSynchronizer synchronizer, Folder folder, SynchronizationPriority priority, CancellationToken cancellationToken)
at MailClient.Protocols.Imap.ImapAccount.SynchronizeIntAsync(Boolean forced)
at MailClient.Protocols.Common.SynchronizableMailAccount.<>c__DisplayClass6_0.<b__0>d.MoveNext()
reason_code = 0
EnqueuedStackTrace =
at MailClient.Protocols.Common.FolderSynchronizer.EnqueueGetFolderList(Folder homeFolder, Action1 completed) at MailClient.Protocols.Common.FolderSynchronizer.MailClient.Storage.Synchronization.IFolderSynchronizer.SynchronizeSubfolders(Folder folder, SynchronizationPriority priority, Action1 completed)
at MailClient.Storage.Synchronization.FolderSynchronizerExtensions.<>c__DisplayClass0_0.b__1()
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.<>c.<.cctor>b__277_0(Object obj)
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
at System.Threading.Tasks.Task.ExecuteEntryUnsafe(Thread threadPoolThread)
at System.Threading.Tasks.Task.ExecuteFromThreadPool(Thread threadPoolThread)
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
GUIStatus_Exception_Reported = True

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Thanks for the fast reply :+1:

Thank you. I experience the same problem with error messages popping up but I am not seeing any fatal errors. I was hoping there was a way to stop the popups

[IMAP] Cannot open folder “/Inbox/Panama/Miranda Contreras/Larissa de Gracia”. (NO [AUTHENTICATIONFAILED] SELECT Invalid credentials)
[IMAP] Cannot open folder “/Inbox”. (NO [AUTHENTICATIONFAILED] SELECT Invalid credentials)
[IMAP] Failed to LIST server folders ( LIST Invalid credentials)
[IMAP] Cannot open folder “/Inbox/Frontline Law/Julie Schmidt”. (NO [AUTHENTICATIONFAILED] SELECT Invalid credentials)

I get these all the time. Has been happening for several months.




[IMAP] Failed to LIST server folders ( LIST Invalid credentials

These are Yahoo server errors “I too now have been getting these same errors alot of the time” since mine initially worked ok using the OAuth setup. It’s a Yahoo server problem and nothing to do with eM Client. Happens with any version of eM Client.

I’ve emailed Yahoo a few times about this but never get a reply back from their technical support. I reckon the Yahoo servers need updating or patching but they are not in a hurry to fix it.

As @ProComposer says above “Outlook and Gmail always work fine” with eM Client and “standalone”. Yahoo Email is a relic that should be removed from the earth for good :+1:

This happens to me too.

[IMAP] Cannot open folder “/Inbox”. (NO [AUTHENTICATIONFAILED] SELECT Invalid credentials)

Oddly, it continues to sync messages just fine, though not always fast sometimes.

I found an article at Yahoo:

It says “If you receive an error message like “Server password has changed” or “Authentication failed,” your app might be outdated. The app likely has outdated security protocols and are disabled by default.”
So according to Yahoo eM is using outdated protocols, rather than Yahoo servers having outdated software or something.

If I follow further, go here:

It says: “If you try to use Yahoo Mail in a third-party email client using less secure sign-in technology, you might get a “Server password has changed” or an “Authentication failed” error message. This is because those email apps use outdated security protocols and we’ve disabled access to them by default now.”
Well, we do get “Authentication failed” messages, so again eM must be using outdated security protocols.

It also says if people have an account key or use two-step, this can be an issue and might be the cause for some people. For me personally, I don’t have those turned on, it’s just my user/pass is all.

Before eM makes the random claim Yahoo’s servers are bad/old/outdated as if they had like one server somewhere on GoDaddy they forgot to update. They have a massive infrastructure like anybody else. They have 225 million users sending/receiving 26 billion messages a day. It’s not likely Bob the IT guy forgot to run apt-upgrade.

I don’t know who is ultimately at fault. Yahoo can connect with the oauth stuff, or an app password, but it doesn’t seem likely it’s their server being out of date. As others have mentioned, there are plenty of other email apps that connect to Yahoo fine while eM doesn’t.

I’m not here to blame because I have not clue which is at fault, but I’m going to guess 225 million people using Yahoo every day from all sorts of clients are doing just fine.

I would at least suggest eM try their darndest to figure out if there is something up with protocols or SSL or encryption keys or storage of data or character encoding or any possible way to make the connection can be a little more robust.

I know it’s easy to say “the server sent an error, so it’s there fault.” Ya, the error is that authentication failed, so why is the authentication failing that eM is trying to send/use?
If I try to log in to Gmail and type the wrong password and it says “authentication failed” I don’t just say “well Gmail’s servers are sending errors, must be their fault”.

Yahoo is only about 7 years older than Gmail, and Gmail itself is practically “ancient” from 2004. So just saying a service is old doesn’t mean anything. They clearly use 2FA and oauth like everybody else.

All I ask is spend a bit more time being absolutely positive, because other email clients continue to work fine while eM doesn’t. Even if it’s just a server error, it’s not like some code bug or accident, there is a reason for the error, something wrong in the communication standards or something. Hopefully eM can work around it, even use “older” protocols or techniques if that’s what it takes.

Anyway, since the email continues to sync, the error hardly makes sense, so I disabled the error popups out of convenience.

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This is a server error. You will need to contact Yahoo! for assistance as their server is broken.

But even though it is a server problem, one thing you can try is installing version 9.1, where we have done some work to reduce the chance of this happening through some workarounds.

You can download the latest version in the Release History

Yes the server sent an error that the credentials were invalid. So why is eM sending invalid credentials?

I can’t accept that the “server is broke”, Yahoo is processing billions of emails a day. eM is still sending/receiving just fine regardless. They probably run entire server farms for this, not one server in some random place. I’d say about 5 to 10 times a day this error is triggered, it seems quite random and doesn’t have any real effect on processing messages. I can’t think of any repetitive task that could be triggering it. Heck, it usually happens when I’m not even using it, like when it’s just sitting in the Windows system tray in the background.

I have it set to check for new mail every 10 minutes. I doubt that is hitting some kind of rate limit.
Hopefully some kind of fix is discovered eventually.

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eM Client isn’t sending invalid credentials. It is the server that is rejecting valid credentials, so broken. That is because it first accepts the credentials, and then immediately rejects them again.

Just because a server process x number of messages doesn’t mean it can’t be broken. You have the error message the server sent you, so please ask Yahoo! to fix it. We have a possible workaround, so you may not see the error again, but the server is still broken.