What is CGNAT?
Carrier Grade NAT (also known as CGNAT or Private IP) is designed by ISPs to save resources, due to the limited number of available Ipv4 addresses like 100.100.255.255.
For each one or a few public IP addresses, there are around 100 customers like you, pooled.
This means you're all sharing one public address among you and all the other people in the pool. Your ISP will then route the traffic to the right person behind the scenes so you don't notice anything.
However, this can sometimes cause issues with port forwarding (needed in Golem for the time being) and gaming, making these ports not visible to the outside world.
But worry not, there is a fix!
Call your ISP and ask them to change your IP to a public one. A dynamic public IP will fix the issue - and most likely won't cost you anything at the ISP. Static IPs also work but most often comes with a monthly fee.