You can see the error on the screen, which is uploaded as an attachment.
mbank is a polish online-bank. When I type in web browser: www.mbank.pl and while it loads, avast throws information, that this site is marked as phishing. On the screen You can see, that the site has valid everything SSL certyficate. Where is the problem?
Until Avast clears the site and removes it from the Virus signature data base you could always exclude the web site (that is if it imperative that you can access the site in a timely manner). That said, I noticed that it is not a secure web site (I looked for an alternate secure web site for this bank which may have actually currently worked with Avast but I could not find any).
I get the blocking using firefox, but differs from Chrome in my popups/information.
The first obscures the site and overlays the Warning - but it gives you the option to Trust this domain - but you have to be 100% confident before you do that.
Expanding the Avast Online Security (AOS) addon doesn’t initially give much information, but the Learn More screen helps - whilst it does mention phishing detected, it also gives clear on malware and also a ‘Positive community rating.’ This I would say probably comes from other avast users that have rated this site as good.
This should give you a little more confidence in allowing it, but at the very leas you should report it as a possible FP as mentioned earlier.