3 accounts and only 1 can send now

Usually, this happens when the three accounts are using one SMTP server. First, click 'account settings' and then click the link in lower left for 'outgoing servers'. that should show three SMTP servers for Yahoo. edit each one's description field to have the email address for that account. Then, do this: - click 'account settings' - highlight one of the yahoo accounts and view the bottom right line name 'outgoing server'. if the email address for the account isn't displayed, click the dropdown menu and select the proper one. Repeat for each account.

Thank you for the information David. I’ll give it a try

Yes, helpful! It explains how to assign the correct Yahoo SMTP server to each email account in Account Settings.

I was glad to assist. ::)