nick Hi Nick, thanks for the quick reply. Yes, both errors (500 and 413) happen when I try to upload the file from my local device when creating a Mastodon post. In the compose box, there is a little paperclip to add media. I click that and browse to the file. After the file explorer closes (i.e. upon upload attempt, even before clicking "Publish" to submit the post) is when the Mastodon UI error message pops up. Happens from any device, but right now I'm trying from Windows on both Chrome and Edge...same result. Happens from my iPhone too (metatext app, Chrome, Safari).
Yup, I agree with your understanding re: optimizing to MP4. I've read the same thing when I've tried to track this down. To me, it seems like it isn't even getting that far in the process.
Another thing that is probably pretty important to add is...I can't play embedded stuff reliably either. As an example, if I view this post on its original site it plays fine: https://mstdn.social/@pollak/109571783072803153.
However, when I view it within my timeline on hoosier.social, I can see a black rectangle where the video would go and I can see the video controls, but it won't play. Not on any device...this Windows computer (Chrome or Edge) or my iPhone (metatext app, Chrome, or Safari browser). Reliably plans when I view it hosted from mstdn.social, but won't play on hoosier.social on any device or under any account. This happens with any video/animated content from anyone that I follow.
I would be happy to create an account on hoosier.social so that someone can log in and see things 1st hand if that would help.
Again, I'm kind of a noob about all of this stuff, but I'm guessing that when my instance pulls posts that I'm following into my Home or Federated timeline, it is also pulling media? And, it is not getting encoded or streaming properly, too.
You suggested that I should submit a ticket if the error still happens on uploads, so I did that through the my.opalstack.com site. I included a link to this forum post as reference.