I also have a couple of subscriptions pending to lemmy.ml communities for a few days now.
Lemmy Support
Support / questions about Lemmy.
Same for me with a couple of beehaw communities. I just put it down to teething issues, which I hope get fixed soon. I wish I could help out but web programming is not something I am familiar with.
I don't know what is going on, but I do know that it is inconsistent. Some of my comments and posts will go through, while others will not. I have one post that I edited after the fact, and hours later, the edit is not reflected on other instances.
I think something is gumming up the works, and I would assume it's the massive influx of people and thus federation requests being sent back and forth between servers. I know for Mastodon that caused some massive CPU overhead because of how many servers each instance needs to contact each time someone posts. It's just text, but when you have to send the same small block of text like thirty times, it gets bigger.
I'm on lemmy.ml and posting to some beehaw threads and sometimes it works and sometimes it doesn't Inconsistent. Some data is making it through, some isn't. I only have a best guess as to why. Nothing from any admins as of yet.
Trying to comment if you see this it went through. In all seriousness though I am also having this issue, unsure if it is just with lemmy.ml though. Comments that are multiple days old have not yet propagated.
I'm currently viewing this post (plus plenty of other lemmy.ml posts) from lemmy.world just fine.