email client does not work with "_" in username

Hello,

I get an authentification error when I try to use an email account with an underscore "_" in the username. I doublechecked typing and my other account (same provider) works fine. So the problem seems to be the "_".

Also the email client cannot handle german Umlaute "ü"...

Is there a way to fix this, or is it a bug?

I'm currently using 0.9.1.5 leak but 0.9.0.5 has the same problem.