When setting up Edge and Chrome, which are basically the same type of browser, you can import bookmarks passwords etc from one to the other so this may account for then behaving in the same way.
When you finish checking your email account, are you logging out of the account or just closing the web page?
Are you logging onto your MyBT prior to using the BTMail button to log on?
Do you log out of MyBT when you are finished using it?
When you get to the BTMail log on page BTMail are you entering your log on details or are they prefiled in?
What happens if you click on the username box? Do you then get a drop down box.
Have tried going into your browsers settings in Chrome and Microsoft Edge and when in the settings go to "Passwords" then scroll down the list until you find "BT.Com.
It will show a number which indicates how many BT.Com passwords are stored by the browser. Click on it and this will then show all the BT.Com usernames and passwords that your browser has saved.
Scroll down until you find your email addresses. You can then click on them in turn and check the password that is recorded against each one by clicking on the small icon to the right of the password.
Check that each email account has the correct password and preferably they should not all be the same.
You can now edit them or I would suggest that you delete the email address and password from the list. It does not delete the email account only the stored username and password.
If you do that you will then be given the option to "re-save" the email logon details the next time you log on should you wish to do that.
