Kibana Error connecting to package registry: request to https://xxx.xxx/xxx failed, reason: self signed certificate in certificate chain

Hello,
In our company we have a checkpoint firewall with a reverse proxy everything works fine except for 1 error message that appears every time you try to access external content from kibana.

log [23: 58: 26.917] [error] [fleet] [plugins] Error connecting to package registry: request to https://epr.elastic.co/search?experimental=true&kibana.version=7.14.0 failed, reason: self signed certificate in certificate chain

The root certificates from the firewall were installed on the Kibana server in the trusted store

Thx
jonkop

Hello,
Is this issue similar to this?