Cannot even connect to vivaldi mail

[gerrus]

Hello,
I cannot connect to vivaldi webmail or mailbox.org.
( googlemail does not work either, but there the problem is well known)

it's always the same error message (see screenshot). what am i doing wrong?

Thanks for help.

[gerrus]

@Gwen-Dragon i tried it at home and it works well there.
hmm, at work i am in a company network, so that's the reason. do any special ports have to be open? our admins are not very "strict", so i am surprised about this now.

probably you can't help me at the moment. thanks anyway!