Cannot send email - Invalid address?

I am o2 pay and go and I was having exactly the same problem.

If you are 02 pay and go click the followin

Settings
Mail, Contacts, Calendars
Mail account in question, usually first option
Scroll down
Go into SMTP
Primary Server
Make sure server is on
Host name smtp. then your providers details
user name is your email address
password is your email password
SSL - off
Authentication - Password
Port - 587

I think my problem was that I was using port 25 and it didnt seem to want to work on that port. Got no problems sendin or replyin to emails now so im happy! Hope it works for you uys, let me know if it does!

Just to add more confusion to the thread. I use IMAP to connect to Exchange. I can send and receive fine except for certain domains. It appears that if the email address is in the format First.Last@domain.com or Name@us.domain.com they fail with the invalid email address. the extra "." seems to confuse the application.

Monaco30 hit the nail on the head. It's an issue with the sending of the user name to the Exchange server, at least for those using IMAP to connect to Exchange. The "." is the issue; for me my user name is being sent as "username.@domain.org"...note the "." after my username. There is a workaround on the Mac side (see comment by sunsworth) and Microsoft server side.

<http://www.macosxhints.com/article.php?story=20020829054506234>.

to sove this go to Outgoing Mail Server, then to SMTP that must be completed with your smt info, then go to Primary Server, with the same info, then to server that must be ON, then fill Host Name with same info an then complete the User Name with you user name as it is in your e-mail address but just up to the @ simbol. Do not include it. And the you Password. It shuold work this way.

Good luck

What a pain, thanks for the info but that doesn't seem to work either... I hope it works for some of the other people.

Hi. My update which solved it for me. I have used email to my IMAP account on my iTouch via wifi for a year with no problems. I got an iPhone for Christmas (3G and 2.2) and set it up the same and it worked too. However I synched up with Mobile Me and I then started to get the 'Address Invalid' issue. I also got this on my iTouch so I know it is related to this Synch and not related to the iPhone, Wifi or O2.

I changed SSL to off but that did not work. I then did the following and it now works for me:

Settings
Mail, Contacts, Calendars
Select the account
Outgoing Mail Server
Primary Server
Add username to your email address - in full
Add your password

This worked for me, not sure why it worked previously without this but I think it was something Mobile Me did.

Note I used Server Port 587 as I saw that there are earlier issues with the same error, where it seems that many ISPs block spam via port 25 so this can cause issues.

Hope this helps somebody. I am in the UK and use O2.
Guy

I had the same problem and after reading the above posts i did the following:

Go into setting on your iphone
Click on Mail, Contacts, Calendars.
Click on the account your trying to use (your default account i believe is used for sending e-mails)
Click on the SMTP field.
Click on the the the primary server that should be displayed as "on".
Once the new menu shows then make sure your user name and password have been entered for the required account.

Then it sent my old messages when i went back into the e-mail app.

Hope this helps.

I have a stranger issue. When I wrote or repled to an e-mail, I now get a message "Invalid sender address" as well. Has anyone received that message?

I'm suffering from the second instance identified by Raleigh D. below. I tried to send an e-mail to two different addresses, but typed one of the addresses incorrectly.

I can still send and receive e-mail, but I keep getting the "Cannot Send Mail -- One of the recipient addresses was invalid" message. It's as if the phone is repeatedly trying to send the e-mail to the incorrectly typed address. Any idea how to stop the problem?

Thank you.

I just had the same thing happen to me today. I find it odd there is no outbox to go to and delete the offending message.

Sure there is.....

Thanks to Guy Emerson - this solves the problem for me as well. What's unfortunate is the "one of the addresses is invalid" message from the iPhone. There's no way you can be expected to connect that to not having configured your SMTP settings to provide the userid and password. The "invalid sender address" that a user further down experienced might at least suggest that you should look at your configuration...

I am having this problem too, and have tried alot of the things i have read, but with no success. Have you figured this out?

Brilliant, trust the folk of Doncaster to provide a solution.

This worked for me, exactly as you said. What is obvious to me is that Apple rushed this phone/app out without a proper set of error messages. There is no "invalid email address" involved in this error, so the error message is totally misleading.

And the lack of Apple input here is worrying, sad, whatever.

I spent 2 days trying to send my wife an important message while traveling and this problem just sat in the way.

Oh well, one problem down, X more to go. Like how did Apple release a computing device without their signature OS feature: cut-n-paste? Can't believe I have to type hemochromatosis over and over on this thing (it's my wife's medical condition, about which I am doing a lot of mobile communicating, the hard way).

Thanks again for a fix.

Thanks. That fixed the problem.