Email-to-SMS problem: address blacklisted

Hi @traskada So sorry for the delay in responding to this. The Community forum is mainly a peer to peer resource and even I don’t have access to account details or ticket systems. Our experts have access to troubleshooting options and ticket systems and there are a few ways that you can reach out to them. You can call in, message through the T-Mobile app or website, or use the Facebook or Twitter icons at the VERY bottom of this webpage to send a message. 

I know that each carrier has a different way of sending emails to phone numbers so a few simple things to mention right off the bat are

• make sure you are sending to phonenumber@tmomail.net The phone number should have no dashes or spaces and not include the 1. 9876543210@tmomail.net for example. 
• make sure the message is simple text or small images. Large images and HTML are not supported. 

One thing that can play a part in your email being flagged by any system as spam is the number of messages you are sending. Since you are only testing right now, I don’t assume you are sending too many messages at this time. If you are planning to scale up, you may want to review our resources on the topic because they may help you prevent issues down the line. Consumer versus Non-Consumer Text Messaging | T-Mobile Support

Hope this helps!