suddenly cannot receive or send ATT email on iphone

We are here to help, @jackyrun.

Here is more information on how to troubleshoot your email. We suggest that you check out the section about the third party mailbox. Also, we recommend that you set up a Secure mail Key or use OAuth. This is required in order for your email to work properly.

Let us know if this helps.

Marc, AT&T Community Specialist

I have this same issue. No email for 4 days! I have changed my password, deleted my email from my iPhone and then reinstalled only to get the same message "no password provided for ATT" Please go to Mail Account Setting and enter a password. The password is in there, in both the outgoing and incoming server setup and still doesn't work!!!  Getting the same issue on my MAC, but can access webmail just fine. This makes no sense and is truly INFURIATING.

Wasted lots of time on this issue myself trying to reestablish email access on my iphone.  Blamed apple at first but think it's ATT's shame and inability to secure their own passwords.  Using the VERY strangely-behaving www.myat&t.com (looks like it was redirecting 5-10 times for each screen change) and viewing my profile, at the bottom there is a link called something like  "manage secure mail key".  Created a key here, and then used this key as the password for this mail account in my iphone settings.  Voila, first view of emails on my iphone since last Nov (6 months ago).  Think the original email password is the same if logging in via desktop, but this key must be used for setup on iphone (read somewhere the words "key is needed for less secure devices")  

The link mentioned in my prior note should now be typed as:   www.att.com/my 

Thanks to heber25355 advice I was able to restart my att email on iPhone 6S.  I got the error message 'no password provided' too.

Sign in to the att account (not email) Found the manage secure mail key feature in my att.net profile (after a help/search) and it is an auto-created key by att after you give it a nickname. (!!?)

The complex password given now should be entered into the Settings on your iPhone for the att email password. Then restart your phone. Old password still works on my laptop. This is for securing the iPhone app apparently, though I do not recall being notified about this. It did work, I got the emails back that were not retrieved on the iPhone, but were still in my desktop/laptop email.