In thread 2023-10-27 Update (Weekend work unit availability), you reacted 6 posts below mine, that's post 690848, in which Error 408 was reported.

According to https://http.dev/408, "HTTP response status code 408 Request Timeout is a client error that is returned by the server to indicate that a request is coming in too slowly from a client and it is unwilling to wait for it to be completed, thus terminating the connection."

If tasks still won't upload, try restarting your BOINC-client.

Adri