Running sudo do-release-upgrade stumbles upon an error:

An unresolvable problem occurred while calculating the upgrade. 



This was likely caused by: 

* Unofficial software packages not provided by Ubuntu 

Please use the tool 'ppa-purge' from the ppa-purge 

package to remove software from a Launchpad PPA and 

try the upgrade again. 



If none of this applies, then please report this bug using the 

command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If 

you want to investigate this yourself the log files in 

'/var/log/dist-upgrade' will contain details about the upgrade. 

Specifically, look at 'main.log' and 'apt.log'. 





Restoring original system state



Aborting

Reading package lists... Done    

Building dependency tree          

Reading state information... Done

I'm attaching apt.log and main.log
https://gist.github.com/omerbn/6e44593d8cab464be7f959b426d1c31c

What should I do next?

Thanks,

O