I know this is an older post, but figured no need to open a new one if a solution can be obtained. However, it seems the endpoint is unresponsive and the CA Feed is unable to updated. Legacy mode does work and I have tried a quick DMZ of my unraid instance with DNS override to 8.8.8.8/8.8.4.4/9.9.9.9 to no avail.
From computer:
$ time curl "https://tools.linuxserver.io/unraid-docker-templates.json" -k
curl: (7) Failed to connect to tools.linuxserver.io port 443: Connection refused
real 0m21.204s
user 0m0.000s
sys 0m0.047s
From an AWS instance:
https://p.catchpoint.com/ui/Entry/PW/I/EY-ETDM-KJ-I8-0-jVmDQERCWr-AV0AR0-jVmDQERCWr-ETDM
From a Cogent instance:
https://p.catchpoint.com/ui/Entry/PW/I/EY-ETDM-ET-I864-0-jVmDQELiyS-AV0AR0-jVmDQELiyS-ETDM