I have tested it on my test site and it’s working fine for me .

I logged in to your site and confirmed the issue.

It seems the issue is occurring because your hosting is blocking requests to github api as described on the following page so please contact your hosing provider to release the block on github api.

https://github.com/ThemeFuse/Unyson/issues/1591
https://github.com/ThemeFuse/Unyson/issues/957
https://github.com/ThemeFuse/Unyson/issues/1938
https://github.com/ThemeFuse/Unyson/issues/1016