Mail repeatedly rejecting account password

Recently, I've noticed that mail repeatedly asks for my account password. I noted that I had to change the password, and for a while that allowed me to continue.

However, now, the password, no matter how many times I change it in Preferences, keeps getting rejected. I've tried restarting and have tried a number of different passwords. Never had this problem before, is there a solution?

Thanks,

Check with whoever is hosting the account. A lot of times, they'll change their mail server settings and it will cause client issues. Typically, most large ISPs and mail hosts will have configuration recommendations for popular clients. Make sure you're setup, following those guidelines.