I was able to write and read once, since that time it always gives the same error, even on a different PC with the same NFC Device ACR122U-A9 <img width="1155" height="692" alt="Image" src="https://github.com/user-attachments/assets/15c4d3df-42ef-4309-ae67-dbb4a1b592d8" /> <img width="1374" height="903" alt="Image" src="https://github.com/user-attachments/assets/385d2fd4-e658-46e2-a766-d436a288584b" /> Tested read and write with my android phone. br michael