My iPhone 6 will not allow me to send emails from aol. Receive fine. I saw others had similar questions?

Email servers require separate ID and password for sending and receiving. Most likely your ID or password for the outgoing (SMTP) server are incorrect or missing. The easiest way to resolve this is to just delete the email account and add it back. You can also go into Settings/Accounts and Passwords and try to fix the problem in the AOL account settings, but deleting and re-adding are the easier way to do it.

Note that if you have 2 factor authentication on your AOL account you will have to generate an application-specific password by logging in to AOL and going to your account settings.