I don’t know what happens in the code of SNAP.
I will try to explain the problem now, but I am not a computer scientist who uses the right vocabulary for this.
We work, as I said, behind a proxy that can be specified in Windows and also in most software packages.
This is also the case in the graphical interface of SNAP under Options, WWW (Figure 1).
There you can also test the connection and it works.
However, if you then want to perform the Orbit file correction, an error message appears (Figure 2).
So it seems that despite the proxy settings, the function does not use the information.
However, we do not use SNAP, but the PythonAPI Snappy, because we want to process mass data, i.e. thousands of Senttinel-1 scenes.
Here there must be a possibility to include the proxy.
The error message is the same here (Figure 3).
I had the same problem elsewhere and was able to solve it. When using the python package sentinelsat I got the same error message when the script tried to retrieve data from sentinel-hub.
The solution here was the following lines of code at the beginning of the script.
os.environ['http_proxy'] = proxy
os.environ['HTTP_PROXY'] = proxy
os.environ['https_proxy'] = proxy
os.environ['HTTPS_PROXY'] = proxy
This solution probably doesn’t work for Snappy, because the package uses Java in the background, not Python. I also set the proxy in Java on my local machine, but without success. I now assume that SNAP brings its own Java environment to prevent problems with updates and not break dependencies.