When I try to add an email account, it repeatedly get a 'unable to verify' message. But email works in webmail

In my experience different email apps can function differently, especially when setting up a new account. Typically it is done automatically. In your case you are going to have to open the email apps Preferences panel and enter the correct identification, and password manually for the email server you wish to connect with. Sometimes other settings may have to be entered manually as well. If you still run into problems, contact that email service provider for assistance in setting up the account. They can be very helpful.