Something about the W11 and Norton 360

A friend has W11 and Norton 360 that she cares about, although I try to persuade her to get rid of them. She wants it because she paid for the license for life   
For a week she has had loss of access to her email by webmail, and also to teamvi.ewer who tells her that she is disconnected, and therefore gives her neither her ID nor her password, but it is not all the time blocked and that surprises me! I tried with my own computer at her house and I have no blocking on my side, so it's neither the network nor the geolocation.
 
However, even after she told me that teamvi.ewer tells her that she doesn't have internet, and therefore that she doesn't have an ID or password, I was later able to access her computer (and obviously, I didn't find anything convincing). Then I went to her house and at first everything was fine, then suddenly boom, no access to her webmail, no teamvi.ewer!
 
Question: can W11 defender behave like this? Could he decide to block his access? I read on a message (but it didn't stay long enough for me to see where it came from) that it is connected to a public internet. Can it also block teamvi.ewer ?
 
Is there a possible conflict between W11 and Norton?