Have you installed the proton bridge software? Are you on a paid account? (free only get web access.)

I have installed Bridge and have a paid account. Tried changing password, signing in without password, still cannot add account whatever I try.

Is your antivirus blocking access to the local host interface used by the bridge? many do because while a legitimate part of computing they claim it is a malware vector that needs to be closed off.

The response I get is password and or user name invalid

I have also tried to sign in 1st without password and then do this later which still does not work. I have tried this again and it appears 5th time lucky I now get the e:mails. Why it did not work before I do not know, I was very carefull to put in correct code, I can understand a couple of mistakes not four, also I signed out after the 4th maybe it reset, I don' know! Thanks for your your help. If I did misstype being able to see a 20 odd random digit password would limit any errors.