First off make sure both iphones have imessage set on in the settings.
Additionally make sure the send as text/SMS/MMS is check on in the settings on both iphones.
Email is sent from the iphones native email program? If so make sure the email settings are entered correctly.
Mail, Contacts & Calendar's is where you can set up the email accounts for both devices. Have your friend test to you and then you test to him.
Hey. Thanks for the reply. Both email and messaging accounts are set up
correct. Checked that. We can send receive emails/texts from other
parties just not to each other over the iphones. Weird huh?
ps. he used to have an android then switched to an iphone. dont know if
that helps any
Go into your contact list and his contact list and remove your contact entry, then you do the same for him.
Then go into contacts and re-enter the contact information for him, and he for you.
Turn the device on and off.
Try sending again.