phone email app will not send emails using mobile data

[#1]

i have used the samsung email app for may years without issue.

Just recently i have encountered issues attempting to send emails over mobile data.

The app does not give much information as to the problem.

today i installed bluemail and encountered the same issue.

"The error is reported as sync failed, your username or password may be incorrect (3010)"

they are not.

"Email server returned: "AUTH PLAIN failed

(535 ....authentication rejected as source IP has a poor reputation)"

As far as i am aware all settings regarding usename and password, starttls port 587 are correct ?

Any assistance would be appreciated. Everything works fine on WiFi

[#2]

@otisbdriftwoodu the IP address you were allocated when on the mobile network has been classed as a source of spam and been blocked by the mail server. The problem with mobile networks is that IP addresses are routinely reallocated from user to user and so if the previous user behaved badly , that poor reputation status is inherited by the new user. In addition, many mobile networks use CGNAT whereby actual public IP addresses are shared between many users which makes the inheritance of a poor reputation more likely.

The poor reputation status usually gets reset within 24 to 48 hrs.

[#3 · Accepted solution]

Thanks for this information, I get what's happening now.

Have also found a work around as the issue has occurred a couple of times.

Use a VPN.

Thanks.