I have experienced the same problem, even with small articles with few references. Keen to see it resolved :)

Update: It ran on Line of Duty (series 1) for each attempt I have tried over the last few days. I haven't tried in nearly 24 hours, so it appears the bot may be trying to work through a backlog. I had to revert the edits though because it removed any intermediate edits I had made since the last time I attempted it.

See diffs:

• https://en.wikipedia.org/w/index.php?title=Line_of_Duty_(series_1)&diff=prev&oldid=1195598969
• https://en.wikipedia.org/w/index.php?title=Line_of_Duty_(series_1)&diff=prev&oldid=1195602425
• https://en.wikipedia.org/w/index.php?title=Line_of_Duty_(series_1)&diff=prev&oldid=1195614759

I have also experienced something similar. I tried to run the IABot on an article I was developing, and it timed out. After a while, I began editing the article again. Subsequently, I was surprised to find that IABot had actually updated the page, but my most recent edits, made after I had assumed the IABot had failed, were lost. This gives the impression that it is working on a large backlog and is well behind, and not able to provide the normal service.

I am also experiencing the same issue as both Marshelec and ThedoctorWho are experiencing: 504 error messages, and the bot running eventually, but overwriting intermediate edits. See, for example, this diff, which overwrote an edit made between the time the bot was initiated and about 12 hours later: https://en.wikipedia.org/w/index.php?title=Kirk,_Kentucky&diff=prev&oldid=1195725129

Same issues encountered here, I have been experiencing 504 Gateway Timeout Error for 95% of my run for more than 4 days already even though the IABot just needed to archive 1–3 sources for my every run, looks to me on surface that it's iterating through every single sources regardless if it has been archived. Also noting that searching for Modify URL Data also take around 5 minutes to load, manually adding archived URL would also throw white screen with the data not saved, seem related to "Fix a single page" run since I believed that both are querying the same database.

It worked for me just now, thanks!

It is working for me, as well. Thank you!