Alright thanks, I filed the task and hope I got everything right.

How do I send an upstream task there? Do I simply add the Upstream tag to the task?

This one is the only page where I tried it

Thanks but as I said in my first post I already tried that but it doesn't actually work; I am currently following the instructions to report a bug on MediaWiki.

I didn't mentioned a wiki because it happens on any wiki I tried it on, but on that wiki it happens more often. I saw it happening on

I tried again and the same error happened, what should I do now? I should also mention that the import works only if the archive is extracted, making the file almost 7 MB big, perhaps it isn't small enough to be imported by local admins like me?

I just tried again and the page showing "error 503 backend fetch failed" appeared. Despite this, pages were imported to the wiki but I don't know if the import was properly completed because of the error.

Thanks, I will try with the other wikis I need to import.

Can you still tell me the interwiki prefix so I can try importing pages by myself in case the file is little? These pages are from Wikia/FANDOM.

I can try. What interwiki prefix should I add when making the import?