Here's more data from the logs on these servers. 24 hours and some of these still haven't sent:
12:35:20:WU11:FS01:Upload 26.55%
12:35:20:WARNING:WU11:FS01:Exception: Failed to send results to work server: Transfer failed
12:35:20:WU11:FS01:Trying to send results to collection server
12:35:20:WU11:FS01:Uploading 1.41MiB to 129.213.40.229
12:35:20:WU11:FS01:Connecting to 129.213.40.229:8080
12:35:21:WU08:FS01:0xa7:Completed 490000 out of 500000 steps (98%)
12:35:26:WU00:FS00:Upload 26.38%
12:35:26:WARNING:WU00:FS00:Exception: Failed to send results to work server: Transfer failed
12:35:26:WU00:FS00:Trying to send results to collection server
12:35:26:WU00:FS00:Uploading 1.42MiB to 129.213.157.105
12:35:26:WU00:FS00:Connecting to 129.213.157.105:8080
12:35:28:WU02:FS01:Upload 14.35%
12:35:28:WU04:FS01:Upload 20.38%
12:35:28:WARNING:WU04:FS01:Exception: Failed to send results to work server: Transfer failed
12:35:28:WU04:FS01:Trying to send results to collection server
12:35:28:WU04:FS01:Uploading 1.84MiB to 129.213.40.229
12:35:28:WARNING:WU02:FS01:Exception: Failed to send results to work server: Transfer failed
12:35:28:WU02:FS01:Trying to send results to collection server
12:35:28:WU04:FS01:Connecting to 129.213.40.229:8080
12:35:28:WU02:FS01:Uploading 2.61MiB to 129.213.157.105
12:35:28:WU02:FS01:Connecting to 129.213.157.105:8080
12:35:28:WU09:FS00:Upload 13.71%
12:35:28:WU01:FS00:Upload 3.33%
12:35:28:WARNING:WU09:FS00:Exception: Failed to send results to work server: Transfer failed
12:35:28:WU09:FS00:Trying to send results to collection server
12:35:28:WU09:FS00:Uploading 2.74MiB to 129.213.157.105
12:35:28:WARNING:WU01:FS00:Exception: Failed to send results to work server: Transfer failed
12:35:28:WU09:FS00:Connecting to 129.213.157.105:8080
12:35:28:WU01:FS00:Trying to send results to collection server
12:35:28:WU01:FS00:Uploading 11.25MiB to 150.136.14.110
12:35:28:WU01:FS00:Connecting to 150.136.14.110:8080
I am sure someone will have informed the necessary contacts, who will have checked if there is an issue - but it may just be a heavily overloaded server. If there is an issue it can take time to resolve - and with the weekend upon us it could take longer. There is most likely nothing you can do at client end to fix this - it may simply be a case of letting the client retry until it succeeds (hopefully it will) or passes the expiration date at which point the client will dump the WU (hopefully not necessary) … Both the WS and the CS look to be up, have disk space and be in "Accept" (only receiving WUs not giving out WUs) so may just be overload of people returning WUs (or trying to).
@uyaem … Looks like the OP is getting connections (variable %ages of upload) so not likely to be a firewall/setup/connectivity issue - has the feel of server overload to me.