An error was encountered while updating the UPM.

[Deleted user]

Fail to upgrade UPM from 3.0.1 to 3.0.2

[Deleted user · Accepted solution]

Follow Updating the Universal Plugin Manager - Update UPM by file replacement.

NOTE: Do not forget delete all atlassian-universal-plugin-manager-plugin-x.x.x.jar files 

https://confluence.atlassian.com/upm/updating-the-universal-plugin-manager-273875702.html

copy new one atlassian-universal-plugin-manager-plugin-3.0.2.jar file from 

https://marketplace.atlassian.com/apps/23915/atlassian-universal-plugin-manager?hosting=server&tab=overview

[Grigory Salnikov]

Hi @[deleted]!

So you've managed to update UPM this way?

[Deleted user]

Yes. worked like charm.

[Grigory Salnikov]

Cool. Thank you!

Have a nice day!

[Brian Warholak]

I recently ran into this same issue, and found that my base URL did not match the URL I was using to access Jira. Once I matched the URLs, the UPM updated successfully using the Manage Apps console.

[Mateusz Kiszka]

@Brian Warholak  Thank you very much !

I have spent couple of hours to figure out why I can't update 'Universal Plugin Manager'.
I could upgrade by replacing file but it doesn't fixe the issue. And then I have read your comment. My base URL was http://my.domain.com but i have accessed jira server using https://my.domain.com. Changing to https://my.domain.com fixed the issue. Although the redirection from http to https is set up

Thank you again.