A friend of mine tells me the instance mas.to (last night, 1/2/24) produced this error message for him:
Due to the technical issues they are having we are temporarily stopping delivery to kbin.social, as the failures and retries are impacting our site performance. We'll monitor the situation and unblock once they're back up and running again.
Figured you'd want to know, and thank you for the service you provide.
Edit: Appears to be unblocked now, but who knows if there are other instances that disconnected.