A browser is what you would use to surf the Internet and yes that is how you access webmail.
Log onto your MyBT and go to Your Products then Mail, manage and check what type of email account you have. It should say "Standard".
If you can send and receive using webmail that means there is obviously nothing wrong with your BTMail email account.
The problem may lie with the BT email server that your device is connecting to.
At this stage the best advice is to do nothing with the email account especially do not delete it from your device or try changing your password.
When this happens the problem usually resolves itself in a couple of days during which time just use webmail.
You could try turning off your BT hub for about half an hour then restart it. This hopefully will have caused it to be issued a new IP address and connected to a different BTMail server. You could also restart your device if you haven't already done so.
If none of that help after a couple of days post back for further assistance.
