AVAST suddenly keeps me from entering my email account

Hi,

I#m using freemail at arcor.de for years now. For the past year Avast didn’t have any problems and I always could enter my email account. However, since yesterday it let’s me log in but when I try to read my email I get a “Thread detected” URL:Phishing" message on all browsers (Opera, Chrome, Firefox). It works on my cell phone (which has another anti-virus than my laptop). What’s the problem here???

https://forum.avast.com/index.php?topic=255052.0