Comment 3 for bug 1845361

Reviewing the log file, /var/log/dist-upgrade/main.log, from your upgrade attempt there was a failure to communicate with the mirror of the Ubuntu archive which you use. This could either be due to an issue with your connection to the mirror or with the mirror itself. Regardless, this is an issue you'll need to sort out by fixing your network connection or switching to a different mirror of the Ubuntu archive before the upgrade can complete. If after resolving the communication error with the mirror you are still unable to upgrade to a new release of Ubuntu please open a new bug report so we'll have fresh log files. Thanks and good luck!