HTTP 400 · Bad Request
HTTP 400 Authentication

When & why it happens

The login code the user entered is wrong. Prompt them again; after several failures the code is invalidated.

Handling in gogram

Surfaced as *gogram.ErrResponseCode. Match on the message:

if err, ok := err.(*gogram.ErrResponseCode); ok { if err.Message == "PHONE_CODE_INVALID" { // handle this error } }