Steps to replicate the issue (include links if applicable):
At https://la.wikisource.org/wiki/Nicolai_Klimii_iter_subterraneum or https://la.wikisource.org/wiki/Second_Latin_Reading_Book select "epub" for export, for example
What happens?:
After a long pause, the user returns to the page without an exported text on Safari, MacOs
After a long pause the user is returned the error "504 Gateway Time-out" on Chrome, MacOS.
What should have happened instead?:
The book should have exported and downloaded on the device
Software version (skip for WMF-hosted wikis like Wikipedia):
Other information (browser name/version, screenshots, etc.):