When trying to save a file I get the error "The authorization mechanism you have provided is not supported. Please use AWS4-HMAC-SHA256 "
I'm using a bucket in the EU-london region and the access key was generated less than a day ago.I've also tried with a bucket in EU-Paris region but it also did not work.
Don't know if it might be related with this but at no point in the code is the Region actually set.
You can try adding the region explicitly in the code see if that changes your result.
Andres Moreno