API to put Multiple resource in SDT getting Authentication failed

If I'm reading that code right (python?) it is just getting an device and not attempting to set an SDT. Is that GET call also failing? When you said other APIs calls work, which do work and which don't?

I don't see an obvious issue with the code, although I don't know python well. Does it work if you don't try to filter the device by displayName and just get all devices? If possible you may want to see if you can verify you are generating the correct signature? Perhaps try making the call in something like Postman?

P.S. I'm feeling old, in that people use emoji in debug messages now... but I should try that! :)