Fix 'yellow dot' upload problem

[roywilly]

No description provided.

[perolavsvendsen]

Subtask (?): Understand and handle the 404 errors

[roywilly]

Tenacity retry code have been improved and long-term testing shows that the number of failed uploads/yellow-dots is very low. However, there are some 404 errors still, and tests indicate that performing retry on these will solve the problem. However, we do not want to use retry on 404-NotFound, so there is made a new issue for the 404 error #30