i get a messages that says the recipient was rejected by the server because it does not allow relaying' anyone know how to fix this?

it will probably be the SMTP settings ,ensure they are as required by your carrier

If they appear correct delete and re enter and if that fails remove that mail setting and recreate

http://support.apple.com/kb/HT4519

Go into Settings>Mail, Contacts, Calendars>your account>Outgoing mail Server SMTP>Primary Server then turn Server ON and fill in both User Name + Password under Outgoing Mail Server.

Thanks for your help. I double checked my SMTP and my username and password weren't saved. I entered them, and it worked perfectly.

I've been having this problem with my iPhone 4 and my iPhone 5, but only when I try to forward messages or attachments from my phone over 4G via AT&T. When I go home and get back on a wireless network, or go to a public place with wireless, the message sends. I am aware the AT&T uses cwmx.com as the outgoing server and I added it as a secondary server. I have tried adding my username and password on outgoing mail on both my regular Email server and over the cwmx.com server - and both won't allow it to save, saying that they don't use password authentication. So none of this helps. Any new ideas?

cwmx.com does not allow username and password ever. If your ISP's doesn't either that means that it will only work when you are on their network. This is unusual, but not unheard of. But CWMX should work. Unfortunately, sometimes it is flakey. And it has limitations on the size of attachments. This may be your problem also. Ask your ISP if they have an SMTP server that is accessible from outside of their network. If not you can use a public SMTP server such as Google's.

Thanks Lawrence. I appreciate the insights. I wonder if this is why I have problems with my laptops with outgoing messages at some hotels. I can always receive but can't always send. Anyway, this helps me understand a bit about what is going on. Maybe it's time to establish a Google mail account.

Worked for me, also checked Authentication >Password. Thanks !

Strangely it was a random occurrence previously, some addresses (even on the same server such as my work colleagues) would be fine but others would be rejected by the server and placed in the outbox.

I had the exact same problem, and went through all of the obvious (and not so obvious) steps. Believe it or not, here's the solution that worked for me: Even though it is listed as "optional" enter your user name (and password, if you haven't yet) in the outgoing mail server. Not sure why, but putting my user name allowed messages to be relayed. Perhaps that should no longer be listed as "optional"...

That is a little confusing; it is "optional" as far as the phone is concerned, but your email provider will generally require it to verify that it is a real subscriber using their network. The only cases where it will not be required is if you are using the phone with your cellular carrier's SMTP server or you are connected to your email providers network via WiFi.

That's what I understood as well. What's odd is that I had no outgoing issues on my old windows phone, without entering my user name...

Thanks a lot m8 , Easy help and worked 100% for me

Had the same issue. Very helpful. Thanks.

Your directions worked perfectly, thank you!!!

Sheri