Sinotrack ST-901 config issues

G.S. yesterday

That's strange. When it receives “set ok,” it seems to be in SMS mode. And the password is correct. Did you make a direct call from your phone, no SMS? If GPS is working, you should get a link back with location data. Or is it working with the Sinotrack App (I never used that really and also skipped the link to their server very fast, after a salesmanager from Sinotrack tried to help me...at least with no success.)?
Otherwise, the ST-901L has various parallel user interfaces based on different standards, and the company updates the software—unfortunately, never to a satisfactory result. Something like that worked: <SPBSJ*P:BSJGPS*D:030> by SMS. Or RCONF0000 where 0000 is the password., Or <CKBSJ>

Possibly your device, if not responding with "set ok" for SMS-commands, just does not understand these commands, I have never received error reports, either "set ok" or nothing.
That’s all from me—keep having fun. The trash can is waiting, after all.