Steps to replicate the issue (include links if applicable):

• Try to upload a file on Commons using Special:Upload

What happens?:

I get a message saying:

Our servers are currently under maintenance or experiencing a technical problem. Please try again in a few minutes.

The details at the bottom are:

Request from 195.213.48.78 via cp3072 cp3072, Varnish XID 657719173
Error: 503, Backend fetch failed at Tue, 26 Sep 2023 16:41:47 GMT

What should have happened instead?:

The file should have been uploaded.

Software version (skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):

This seems to be a general problem affecting Commons, at least. https://commons.wikimedia.org/wiki/Special:NewFiles shows only twenty uploads in the last hour which is surely not typical. Also, https://commons.wikimedia.org/wiki/Commons:Village_pump#Upload_error indicates that others are having problems.