How to install this plugun?

[Nikita Evsey]

I see this error when trying to install it

http://joxi.ru/gV2VkwF0Lz5KAv?d=1

It worked fine for a while and now it not installed anymore and I can not install it again.

[Nic Brough -Adaptavist-]

It's a Connect add-on, you install it from "manage add-ons" in your Cloud Confluence.  The error you're getting implies you're trying to install it on a Server.

[Nikita Evsey]

Nic, thank you for the response, but I use cloud version of Confluence.
And I am trying to install it through “Find new add-ons”
http://joxi.ru/K823eyC6GbRWrO?d=1

[Nic Brough -Adaptavist-]

Hmm.  Then there's something wrong with the add-on - it's reporting itself as a Server add-on rather than Cloud.  I think you'll need to raise it with the vendor.