user name or password for email is incorrect

After the last ISO update, I'm having a very difficult time with my Verizon email and being able to send emails. I can receive fine I just cannot send. I get the error message "Cannot Send Mail - the user name or password for xxxxxxx.net is incorrect. I've deleted my account several times and then went in and put it back on and still the same error message. I've followed on the tips on support site and still same error message. What am I doing wrong. Can anyone help me? I appreciate any help. Thank you.