I recently changed my email password. Now I can receive messages but not respond or send. Help

This is just me... But I'd try contacting AOL about it.

Are you using the browser or the app?

Most e-mail accounts need to be configured when first set up and this includes matching the password to the Post Office Protocol (POP mail) to receive and to the Simple Mail Transfer Protocol (SMTP mail) to send. AOL may also require a password authorization and if the passwords don't match you can't send. Look in the menu or tools and look for something like options, account setup, mail connections, etc. Find the window for setup and where it lists SMTP, and if it asks for a password put in the new one. The POP mail usually defaults to the new password. Also do a search of your problem on you-tube, they have a lot of good stuff.