Emails not working unless I turn avast off

Hi,
I have purchase avast - I think element 5 - and everything was working fine, but since a recent upgrade my emails wont send or receive unless I turn avast off, which is both annoying and defeats the purpose of having the program. I have also had an issue where I can’t access certain pages online (ie;my bank statements). I haven’t changed any of my settings, and all of these things used to work.
Can anyone advise what I can do so that I stop having this problem?
Thanks,
Jane

Which version of avast are you running and which Management console?