Problem logging in to Google hosted email domain

Sorry this is kinda long, but I wanted to include all relevant information.

UPDATE: See my reply to this post. Google has changed the logon protocol for 3rd-Party email clients to DISALLOW logging on with just user name and password, instead requiring support for OAuth. I’m not sure why two of my gmail accounts work in eMClient, while the third one does not.

I have three email accounts set up in eMClient. All three are gmail accounts. All three are IMAP/SMTP. However, only two of them have an “@gmail.com” domain name. The third one is a private domain name HOSTED BY GOOGLE, set up by my brother, which I’ve been using for years. Suddenly, I cannot log in to this account from eMClient.
Instead, I get an error message saying "Server says “Invalid credentials (Failure)”.
I have entered the correct User name (email address) and Password, but there seems to be nothing I can do to get it to log in.

I have checked using the Gmail Web portal in Chrome, and can still log in with the same user name and password. What’s more, I can still log in to the account with the email client on my Android phone, and it is keeping my Inbox updated.

I tried: Click “Accounts” on the eMClient main menu.
Clicked the name of the account ([email protected])
Clicked the IMAP tab. I tried using the radio button for “Use identity credentials” No joy.
I tried the radio button for “Use these credentials” and manually entered the User Name
and password. No joy.
I did the same on the SMTP tab.

I clicked the “Diagnostics” tab.
It says: IMAP: “?” (Question Mark) Unknown
It says SMTP: " " " "

There’s a button that says: “Fix”. It then tries a number of imap logon addresses, including a couple that actually look like they might be correct, using Port 993, as well as 143. But it never succeeds in logging on.
It comes back with a message: Server (__Link to Server Name) requires authentication. Do you want to send your credentials?
I then select the tic box for “Do the same for the rest of the discovery”, and click “Yes”

I clicked the "Enable diagnostics logs for: and checked the tick boxes for IMAP and SMTP.
Then, I clicked “Diagnose”
Then I entered the User Name & PW for the account.
It then says “Testing” with a progress icon.
Eventually, it comes back and says:

“Autoconfigure failed. An email server was detected, however, your credentials were rejected”
“Do you want to try again using a different password or username”
It doesn’t matter what I do. It won’t log me in.
I can also click the “Diagnose” button, but the results are the same.

This is alll I can do

Please help!!

ok… So Google is now restricting logon access to apps that use OAuth. I’m not sure why my other two gmail accounts are continuing to work, but maybe that won’t last long???

Recommended email clients

We recommend you use Gmail only with third-party email clients that support OAuth. OAuth lets apps and websites share your Google account data without requiring your username or password. Email clients that use OAuth keep your Gmail account more secure.

The latest versions of Outlook, Apple Mail, and Samsung Mail support OAuth. If you’re not sure if your email client supports OAuth, contact tech support or check the help documentation for the client. Learn more about OAuth.

Yes Google advised back in 2022 that they were going to disable legacy usernames and passwords and were moving to all OAuth token password logins as per the below eM Client blog.

That change was officially completed at Google as of September 30th 2024 as per the Google blog further down. So all accounts from then on now have to be setup in eM Client via the “automatic acct wizard” which then uses OAuth with Personal and Business Google Accounts.

(Google ‘less secure apps’ access and what it means for eM Client)

(Less secure apps & your Google Account)

(eM Client with Google Workspace Setup)

https://www.emclient.com/em-with-google-workspace

I had no idea. Thanks for the information. I wonder if there was some way I could have learned about this without my having to waste so much time in the process. eMClient was stunningly UNhelpful, as it went through the process of trying to “fix” the account login procedure. Is there NO WAY it could have identified the problem and alerted me.
As it is, I’m now recreating a new mail account with the new authentication protocol. It’s now synchronizing a huge number of emails into what will be a “parallel” account on my local drive. This seems like a tremendous waste of resources. Of course, I have no idea how this all works… but it’s been downloading for 3 hours now, and I don’t think it’s halfway done. My one TB hard drive is getting perilously full. I hope it will be able to complete the synchronization.
It’s my understanding that if I simply delete the old account, the local contents will still remain on my local drive. If you know of any recommendations for how and when to delete this information, I’d appreciate it. I don’t think a simple “Delete” will work, if it attempts to put the contents into the “Recycle Bin”. I seriously need to clear out some space.
Anyway, thanks for your helpful reply.