6 months of “Authentication Error” all settings are correct. Other email clients work fine. I like eM, but this, and your failure to fix it . . . well . . . uninstalling soon.
Hope you address this issue. Lots of people have this problem. when are you going to fix it?
Thank you. 
Hello,
we would appreciate if you 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 using the same logging settings window.
Regards,
Milos Kovalcik.
Thanks for the logs. Apparently the authentication succeeded when the logging was enabled, so it is probably some intermittent error.
The server running on the optimum.net domain accepts user names without the @optimum.net suffix and it runs a Sun Java Messaging Server.
The only similar problem I could find was the following:
http://www.outlookbanter.com/outlook-…
Oh yeah, being in IT industry for 15 years… I love this type of problem describing and the attitude on how he/she’s going to fix it.
Well actually the nice people at eM fixed the problem.
Um . . .
Do you understand frustration Mr. IT expert? After months of annoying pop ups and failed emails?
Unfortunately I am not just as smart as you:-(
Now, a little ad hominem for you:-)
If you don’t like the way my question was posed. . . .
Well . . .you can kiss my a** 
I am amused.
Thank you for your help Filip, and the link. The issue seems to be resolved.
Thank you, eM is a great email client, I dumped Windows Live mail:-)
Thanks!
No more than frustrated with Microsoft with some of the problems they have with any Windows. No more than amusing that Windows7 doesn’t even come with an e-mail program. Emm, yeah " and your failure to fix it . . . well . . . uninstalling soon" is a great mature statement to get people help you. It even more amusing that all of the sudden the eM people are “nice” after they fixing the problem for you.
If you are that unhappy you can “uninstall” it. And choose, let say… Thunderbird?
If you just need help, you don’t need to tell people that if it not fix soon, you ARE going to “uninstall it”.
This a community support for the free users. Sure you can understand that? Not trying to pick up a fight, just saying - you don’t need to say it that way.
PS. World peace man!
ok . . . I"m frustrated, you’re frustrated, we’re ALL frustrated . . . 0_o
Perhaps I was a bit terse >_<
I am still trying to get my jaw back into place after it dropped after seeing that my brand new hot out of the box Windows 7 Pro had no Email client. Filed in my MS head up ass folder. 
Uninstalling is MY solution to “fixing” software that annoys me for too long. I never made any claims to maturity, and I reserve my right to be snarky :-9. I know, you hate emoticons.Get OVER it.
Fortunately the nice people at eM Client have the ability to look beyond my idiosyncracies and focus on the issues, and thank you for reminding me to thank them publicly, in addition to the email I sent to Filip personally thanking for his help. Sometimes I forget, I spend a lot of time these days being frustrated . . .
I am thrilled that humbled little me brings you such amusement. Have you considered a hobby?
Yes, I agree, I could have chosen a more charming approach, but, please refer to “frustrated” above. But it is always helpful to have a little trolling to straighten me out, ,/ \m/
I sincerely apologize to the horror I must have engendered at in the neighborhood with my post, they are probably just getting over the trauma. . .
I am sure my missive would wipe the smile right off of Mr. Rogers face. . . .
Just saying. . .
Peace out Dude!
LOL, beside going to theatre, watching or playing soccer, listen to music, reading through forums and see some of the post unfortunately is one of my hobby.
But eM Client is one of the better choice for free e-mail, I’m just doing a little of my share to help the free community. I’m mean I’m sure you aware most if not all freeware program don’t have this type of support. I’m just glad there’re actually eM employee participate.
And I’m cool with the emoticon 
0_o
I’m experiencing the same error with setting up calendar and contacts using an apple osx.8 server. Any ideas why?
In the first place open the account settings and remove the domain part of your username - it should help.