@emptyowl 

Not sure if this is going to help, here a similar case and solution is to change the number generated by a client  in binary format.

https://stackoverflow.com/questions/28488691/http-400-bad-request-while-authenticating-with-onvif-camera

  @Little_C Thank you, I'm using a PasswordDigest provided by the onvif Python libraries and they work with other cameras, that's why I'm starting to think that the credentials are different. I found another Python libraries which is not official, is called pytapo and it works fine but it has been implemented by reverse engineering the Tapo APP and it uses JSON over HTTP.

Nonetheless I'd really like to be able to use the onvif protocol using Python