No Data or Group Texts via AT&T

Technical Support
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I received my Mudita Kompakt today, got a new physical SIM card from AT&T with the number from my iPhone 13 mini that had an eSIM. Upon putting the SIM in the Kompakt after updating the phone I received a message stating “The device you tried to active does not work on our network.” I tried adding an APN to match the one described in the forum post titled: MMS issues on ATT but have had no luck. Where do I go from here? I would love to be able to use this phone but I do need it to be able to use maps and other features which require mobile data.

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I have success with mint mobile sims / it’s t-mobile

Google says:

Workarounds & Troubleshooting

If you are determined to use the Kompakt on the AT&T network, try these proven workarounds:

  1. Activate via Smartphone First: Do not insert the SIM card directly into the Kompakt out of the box. Activate your AT&T SIM in an officially supported smartphone first, and then transfer the active SIM card into the Kompakt.

  2. Manually Configure APN: If your mobile data or MMS does not work, you may need to manually update your Access Point Name (APN) settings in the Kompakt’s network settings.

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Unfortunately I am unable to consider switching plans at this time, so I will go to the AT&T store today to get a new SIM card activated and try the two steps you mentioned to see if they work. I did configure the APN manually but it was after I inserted the card into the Kompakt for the first time, so this time I will start by putting it into an officially supported phone first, updating the APN manually, and then moving the SIM over to the Kompakt.

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@noatak Welcome to the Mudita Forum. We’re glad that you’re here.
You mentioned that you’re transferring from an iPhone. Did you de-register from iMessage?
Additionally, it might be helpful to de-register from RCS as well.

As a side note- An AT&T user posted this workaround awhile back- I saved it.

If you are missing certain SMS or MMS messages on your Mudita Kompakt, please follow the steps below:

  1. Check if the issue occurs with long SMS or MMS messages.
  • Ask the sender if the missing messages contained photos or were unusually long.
  • Sometimes, long SMS messages are sent via the MMS protocol by certain carriers.
  1. Verify your APN (Access Point Name) settings.
  • Go to Settings → Network & Internet → Mobile Network → Access Point Names (APN).
  • Select your active APN profile.
  1. Compare your current APN settings with the official settings from your mobile carrier.

  • Visit your carrier’s website or contact their support to confirm the correct values.

  • Pay special attention to the following fields:

  • MMSC

  • MMS Proxy

  • MMS Port

  • APN Type

  1. Make sure the MMS Port field is not blank.
  • If the field is empty, enter the correct MMS Port number as provided by your carrier.
  • Example: For US Mobile (AT&T / “Dark Star” network), the correct MMS Port is 80.
  1. Save your changes and restart your phone.
  • After restarting, send and receive a test MMS (such as a photo) to confirm that messages now arrive correctly.
  1. If the issue persists:
  • Double-check all APN fields for typos or missing values.
  • You can also try deleting and re-adding the APN profile with the official carrier details.
  • If problems continue, contact your carrier to ensure MMS is enabled on your account.
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