'SIM Not supported' error message with ATT

[Mobilemobile16]

We are using RGKNSE R-Sim 15 jivvy sims for unlocking iPhones to other carriers. We have not had any issues with the updater dongle or the jivvy sims other than with what seems to be only ATT devices. No matter how many times we try, or double check our process the issue keeps coming up, and only with ATT phones it seems. The rsim menu will pop up, we choose iccid unlock and put the current code, but then "sim not supported" message comes up. Our dognle is updated to 19.3
This is the process I use;

1. Check if the ESN is blacklisted
2. Check with the new carrier to make sure the IMEI will work on their network
3. Update ios to 13.5.1
4. Put new Sim card with the rsim, into the updater, wait for green light.
5. Take sim tray out and put it into iphone.
6. Wait for the first menu, and choose ICCID activation
7. Choose ICCID Unlock on the second menu
8. Type in 89014104279605344290 and click accept
9. Click accept on the final screen.
10. Log into wifi, wait for activation, and test the device on new network.

This process usually works with no issues, ive only had this 'sim not supported' error on att phones.

Am I missing a step or something? Thank you.

[kinglock]

new iccid
89014104279605344290
89014104279605344274