Messages on iMac with Catalina no longer sends files
I recently upgraded to Catalina and I was using the Messages app with no issues. It would send texts and files like normal. Then about a 4 or 5 days ago, it would no longer send files, no matter what type. I've tried almost all the things I can find on the internet about logging in and out of my accounts on my iMac and iPhone, deleting .db files from the Library and from other locations (which requires a restart on the computer). I don't know what to do as I've changed nothing and it has just stopped being able to send files. I can still send texts normally, even to SMS and group chats.
When I do try to send a file, it immediately pops up as failed to deliver. If I try to send it to myself (my iPhone number), it hangs on the upload line at the top of the window at about 90% or so and never finishes.
Any ideas on what I can do to try to remedy this?
iMac 27", macOS 10.15