Can't Reply or Forward Emails

Any advice would be appreciated!

Is it a hotmail address?

No, I have both me.com and outlook. Neither one will let forward or reply.

...did this just start today? Did you happen to try the usual, restart the phone, etc?

And, can you receive emails okay?

Go into settings > mail > click on your email address and check the Incoming mail server & outgoing mail server is filled in / correct .

I can send emails, I can receive emails, setup is correct, turning off and on has no effect. Thanks for your replies, I'll keep trying.

I had the same problem until my son showed me what was wrong. Got to settings then go to smtp and click on that then click on your servers and make sure your username and passwords are filled in. Once this is done you should be fine.
Hope this helps