Can't sync keys within one bucket?

[NickStefan]

EDIT for clarity:
I'm able to use the aws CLI and keys like this:

aws --endpoint-url https://s3.amazonaws.com s3 sync s3://bucket/key s3://bucket/other_key

But when I try something similar here

s3sync --tk KEY --ts SECRET --tr us-west-1 --sk KEY --ss SECRET --sr us-west-1 --se https://us-west-1.s3.amazonaws.com --te https://us-west-1.s3.amazonaws.com s3://BUCKET/key/ s3://BUCKET/OTHER_KEY/ -d

I get an error about The authorization header is malformed; the region 'us-west-1' is wrong; expecting 'us-east-1'

Synced: 0; Skipped: 0; Failed: 0; Total processed: 0onHeaderMalformed: The authorization header is malformed; the region 'us-west-1' is wrong; expecting 'us-east-1'

I'm 1000% sure my bucket is in us-west-1. The command works with aws cli. The keys work. The S3 bucket is in us-west-1. Any idea what the issue might be?

[NickStefan]

I dunno. I removed the --se and --te custom endpoints and it magically worked? I tried all sorts of combinations of endpoints:

https://s3.amazonaws.com
https:/us-west-1.s3.amazonaws.com
etc...

I feel like it should work with one of those? But I might be missing something. Apologies for the issue.