iOS Email login fails consistantly

Yesterday afternoon I noticed hundreds of Delivery Failure messages flowing in with thousands of email addresses listed as attempted. Of course, I did not send any of these emails. The error was something about a maximum of 150 emails would be send per hr. There was a spammy looking attachment as well...

These emails appeared on my iPhone and in my Roundcube web mail. I thought that I had been hacked so I changed my email password. The emails stopped.

However, now, I can login to webmail with my new username and password, but all other devices fail, despite updating my password, deleted my account on my iPhone, and re-adding. I've tried changing the password several times nothing works.

Despite driving myself crazy I cannot login from my iPhone. However web mail works. My web host was unable to figure out the issue. I am hoping someone here can help me. I have verified all setting dozens of times, including using the autoconfig. It is always the "The user name or password for "Account Name" is incorrect." error.

As mentioned, everything was previously fine until yesterday when the messages started rolling in and I changed my password. Since then, no matter how many times I change my password in cPanel for that email account I always fail on iOS, but always can get in through web mail.

Does anyone have a clue what in the world may be going on? Could the server be blocking by device from connecting? My web host could've resolve, so I'm hoping someone can let me know what to tell them to fix the issue.

Thanks,
Jon

 

So it looks like my email address was "graylisted" which the first service rep at my hosting provider failed to uncover. Instead took the easy route and said "it must be an iOS issue"

I am still concerned though that there was malware installed or a hack by which thousands of spam emails were send from my account.

Am I able to run this through cPanel? Not sure how to go about this, but I really want to scan to make sure there isn't malware...