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Shawn, Computer Engineer
Category: Mac
Satisfied Customers: 275
Experience:  15 years of Mac software and hardware troubleshooting experience, 10 years of programming experience
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When I try to send an e-mail, the iPhone responds that the

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When I try to send an e-mail, the iPhone responds that the recipient e-mail address is invalid. I've checked carefully and there is nothing with the recipient e-mails that appears invalid to me.

Try sending an e-mail to another e-mail address. Does it work?

Kind regards,

Customer: replied 8 years ago.

no, i've tried several



Ok, then the problem is with your outgoing mail server settings. On the iPhone,

1) Go into Settings
2) Choose Mail, Contacts, Calendars
3) Press the name of your mail account under the "Accounts" heading
4) Go down to the Outgoing Mail Server heading and press on the SMTP line
5) Press on the entry under "Primary Server"
6) Make sure the settings here match up with what your e-mail service provider has given you. In particular, you might try re-typing the password XXXXX make sure that it's right.

Let me know how this works for you. Kind regards,

Shawn and 3 other Mac Specialists are ready to help you
Customer: replied 8 years ago.

I've tried that. I just went in and retyped the password. However, on the Outgoing Mail Server, my e-mail service provider requires authentication. When I tap "authentication" on the iPhone, it replies "MD5 Challenge-Response" "NTLM" and "HTTP Md5 Digest" all of which is meaningless to me. Where it says "password", which seems to be highlighted, there is a check mark. I get the impression this means it is using the login.


I'm stumped.



Ok. Can you tell me who your e-mail provider is, and the name of your outgoing mail server? I'll see if I can find what the authentication type is supposed to be set to then (it differs based on email service).

Thanks! Kind regards,

Customer: replied 8 years ago.

Hi Shawn,


I went back and entered the "optional" username and password. Lo and behold, I was then able to send an e-mail message successfully. Thanks for your encouragement, and confirmation that the problem was in the outgoing mail server. It gave me encourage to keep trying. It was difficult to get the password XXXXX "stick." I don't know why, but once it stayed put, the problem seemed to have been overcome.


Thanks very much.

Wonderful, I'm so glad that it's working now and to be of help! Thanks for letting me know, and for using JustAnswer!

Happy iPhoneing,