Why does VK api return Error 121: invalid hash?

Question

Python

Problem with saving photos to photo.saveWallPhoto(). I send the correct hash, but the server returns an error:

{"error":{"error_code":121,"error_msg":"Invalid hash","request_params":[{"key":"oauth","value":"1"},{"key":"method","value":"photos.saveWallPhoto"},{"key":"server","value":"844417"},{"key":"photo","value":"[{\"photo\":\"c6d1bf1e15:y\",\"sizes\":,\"latitude\":0,\"longitude\":0,\"kid\":\"675e08a05bbf87803b0370f30e3efc81\"}]"},{"key":"hash","value":"1af7b024434ca7a0fe62f68e9ed2a9a0"},{"key":"v","value":"5.0"},{"key":"group_id","value":"****"},{"key":"user_id","value":"****"}]}}
[{"photo":"c6d1bf1e15:y","sizes":,"latitude":0,"longitude":0,"kid":"675e08a05bbf87803b0370f30e3efc81"}]

I am writing in python 3.6, I looked for answers on the Internet, but I did not find anything for myself

Answer 1

Check that you are following the instructions for uploading photos to the VK wall correctly.