how can I install add-on without plugin as it is not working

[Joanne]

My add-on admin page in JIRA is showing 'The Atlassian Marketplace server is not reachable.' - no idea what is going on here but I need to install some add-ons sooner rather than later and I am wondering can I do this another way and not through the ADMIN function if it is not working!

[Nic Brough -Adaptavist-]

It means your JIRA server can't reach the marketplace for some reason - I can reach it, so it's probably a network issue on your side.

To bypass the need for a connection, go to the marketplace in a browser, find your add-on, download the right version and then use the "upload add-on" function in the add-on management page.