Known errors

I keep getting HTTP 401 Unauthorized messages

This means that the given username/password combination is incorrect. Note that if you created your account recently it could take a while (a few days?) until you can use that account on apihub and therefore sentinelsat too. You can go here to test access on the apihub endpoint.

The query fails with HTTP 500 connection timed out

Scihub servers are known to have outages due to high demand, try again later.

My search returns 0 results

Maybe there are no images for the specified time period, by default sentinelsat will query the last 24 hours only.

Anything else?

Make sure to check the issues on GitHub too.