Installing Hacks custom integration fails using ZeroTier?

When I try to install custom frontend and integrations from Hacks accessing HA through ZeroTier, installations do not complete. After clicking «download» for a custom integration or a custom card, download icon just spins. When logging in directly with ip:8123 everything works. Challenging when maintaining the HA installation in our summer house from remote.

Is this a known error, and any advice for workaround?

Please don’t create multiple posts for the same thing.