My company is having issues with T-Mobile users not receiving our notifications, sent out as an email to their phones as a text message using "email@example.com" . We have tried anything and everything we can, but keep get the errors like the one copied below:
Arrival-Date: Mon, 18 May 2020 16:52:25 -0400
Diagnostic-Code: smtp;550 permanent failure for one or more recipients (firstname.lastname@example.org:blocked)
I've tried many things shown in the thread below, but nothing seemed to help. I was wondering if you could give us a hand with this? Also, the dispatch email address is email@example.com . It seems we need to get whitelisted in order to get around being blocked.
Best answer by tmo_ian
If you check out the correct answer in E-mail to SMS being blocked due to suspected SPAM, due to CTIA updates commercial text messages are no longer allowed through tmomail.net email addresses. If you wish to send out notifications for your business, you'll need to invest in a short code service that allows customers to opt-in. There is no whitelist that we can add you to.