unable to send emails

hello,

yesterday we've changed the passward for our domain email, ever since every time we try to send e-mail via zoho we're getting an error massage . we received the following masage today:

how can this be resolved?

Username and Password not accepted :Authentication failed

This account __________has been configured in Zoho Mail for fetching mail via POP. A Mail Fetch failure

error occured for this account. This could be due to Authentication Failure for this account. Hence auto-fetch for this account has been disabled. Kindly change the Mail Settings in Zoho POP Settings page

and re-enable auto fetch. Thanks.