Keep getting error message "An error occurred. Invalid first reply"

For the last three weeks or so, ever since the second-to-last upgrade, eM Client keeps giving me this error message: "An error occurred. Invalid first reply. "

I run multiple email accounts (around 18 in total), and have eM Client set up to check them every ten minutes.

I now find that eM Client will check the email accounts correctly once – and then will give me the same error message across multiple accounts every other time (although inconsistently, with some emails getting through). I can look at my email accounts directly through webmail and see emails sitting there, but eM Client often doesn’t clear them, giving me an error message instead. Then, every so often, it works on some accounts. As a result, new messages are shown in the new emails pane – but they won’t necessarily be at the bottom of the list, if later emails addressed to other accounts have been downloaded earlier.

The only workaround I have found is to keep restarting the programme. As you can imagine, this gets old real fast.

I am a paying customer of eM Client, and signed up about three months ago when Outlook Express stopped working properly. I thought I had found a good alternative, but this is driving me crazy. Please help.

I reported this problem via this forum nine days ago but have had no response.

Please supply us the whole log from the Log tab of the Operations window. Certainly it seems to be problem with specific POP3 server or its settings.

And it continues on like that for page after page

The sign at the top of the page says “eM Client employees are here to help.”

Clearly not much, and not for long.

Hello Michael,
I am sorry for the delayed reply. Firstly, as a paying customer, you should have received an email with access to our commercial support system. If you haven’t, please let us know at [email protected] and we will resend it to you promptly.
Concerning the issue: there has been a problem in one update causing a change of the accounts’ settings, namely the Port and Security policy fields in the account’s POP3 tab - please check that the currently shown settings match the settings as required by the email service. If the settings will be fine, we can work on this together through the support system once you contact us on the mentioned email.

Libor Grafnetr

I am having this problem as well, and it is becoming very distracting. Has anyone come up with a fix yet?

Nope. Went away by itself for a while when I rebooted my computer.

Now it’s back with a vengeance. I have absolutely NO confidence that my various email accounts are being checked, so – until I can replace this program with something that actually works – I have to keep checking via webmail.

That doesn’t sound too promising. Thanks for the feedback

Unfortunately now I am in the same situation.

I am building a new computer now. All parts are new (except mouse).

I copied my emClient *.dat files and settings.xml from the old computer to the new one. On both computers I have emClient 3.5.11809.0 installed.

On the new computer during the checking of incoming mails the symptom occurs what others described above. On the old computer everything is still working.

Here is my log content:

2:03:29 [email protected] [POP3] Connecting: To [email protected]
2:03:30 MailExceptions.Exception: Invalid first reply:
2:03:30 a következő helyen: MailClient.Pop3.Pop3ReceiveCommand.Connect(WorkerStatus status)
2:03:30 a következő helyen: MailClient.Pop3.Pop3ReceiveCommand.Execute(WorkerStatus status)
2:03:30 a következő helyen: MailClient.Commands.Command.Process(WorkerStatus status)

I thought it was an antivirus or a firewall issue but when I switched off both of them, the problem still was there.

I really do not know what this error is and - seeing that others can have the same problem for years - it should be investigated.

If You think I can help then I certainly would. If You send me some bughunter version of emclient to replace the existing version with it then I would do it. I just want to eliminate this problem.

Please help, otherwise I can not use my computer.

this issue is really embarrassing. Please fix it in any way. I promise I will try to help if I can.

Nothing happend until now? No statusupdate? No word ́s like: “we will fix it soon?”
I have the same Problem now.

No, unfortunately there is no answer…:frowning:

I had the same problem as You can see my comments from 3 months ago.

That time the problem was that I was migrating from one computer to an other one. On both of them I had WinXP SP3. After installing the OS and the same version of EmClient (and some others) to the new XP, I copied the emClient files from the old PC to the new one.

That time I got this error message.

I did not receive any answer from so I deleted my account from the new PC and all of my mails. I recreated the account with empty mailbox, exported all of my mails from the old PC into *.eml format and imported them to the new PC.

This is not perfect solution because

  • had to recreate all of my folders manually
  • I had to recreate all of my rules (I had several one)
  • the client did not know which email did I read and which not
  • I had to recreate my addressbook
  • etc.

So this is really not the good solution.

Anyway, I was lucky because I had the emails from a working emClient version.

If You are not so lucky then I can not say any good news to You.

Maybe emClient developers read this and try to solve the problem?

Till that time I suggest to archive Your mailbox directory. Maybe the developers will benefit from it if they want to bughunt this issue. But they seem not to be so responsive so I am not sure…

Sorry for bad news.

I ́ve same Problem with my eM client. I ́ve checked account settings

  • ports for smtp / pop3 service setting right
  • settings for secure connection also setting right (disabled it)

Problem is the same. Here is my Info:

I ́ve just installed eM Client and configurate about 6 pop3 accounts, imported from outlook. When clicking on send & receive, two errors ocurred in the operations dialog. The logs printed the following:

12:24:16 [email protected] [POP3] Verbunden: An [email protected]
12:24:16 MailExceptions.Exception: Ungültige Antwortadresse:
12:24:16 bei MailClient.Pop3.Pop3ReceiveCommand.Connect(WorkerStatus status)
12:24:16 bei MailClient.Pop3.Pop3ReceiveCommand.Execute(WorkerStatus status)
12:24:16 bei MailClient.Commands.Command.Process(WorkerStatus status)
12:24:16 MailExceptions.Exception: Ungültige Antwortadresse:
12:24:16 bei MailClient.Pop3.Pop3ReceiveCommand.Connect(WorkerStatus status)
12:24:16 bei MailClient.Pop3.Pop3ReceiveCommand.Execute(WorkerStatus status)
12:24:16 bei MailClient.Commands.Command.Process(WorkerStatus status)

This error occures everytime, eM client looks for mails. Also, when the automatic (30 mins) is activated.
When eM looking for emails, the error occures at the first account, next time on the 4th and anothertime on the 2nd account. It ́s exactly the same error, except the account ́s name and email address :slight_smile:

Do anybody have an idea, to solve this problem?

tested on OS: winXP 32Bit / Win 7 64 Bit

Do you need further informations?

Do you have a Pro license?

Yes, I have.

You need to wait an employee from eM to analyse you internet traffic log.

I apologize for the delay in replying. Please send us logs: go to menu Tools->Settings->Logging and check Network communication.
Then restart eM Client, try to simulate the issue and send us the logs (with reference to this topic) using the same logging settings window.
Thank you.

George Wilson
eM Client

Has this issue ever been resolved? I have the same issue.

As much as i know, there is no solution for this. Except the one which was useful in my case (see my long comment above). I know, my one was a special and rare case but maybe it helps You too.



I too am getting this error & am only a new user, wondering if a fix has come about yet??