Update:
The same is happening with Github action runners
Error: error creating Team information: POST cloud.mongodb.com/api/atlas/v1.0/orgs/5e85b39c70ff62663a3df63a/teams: 403 (request "IP_ADDRESS_NOT_ON_ACCESS_LIST") IP address 40.65.198.72 is not allowed to access this resource.
However, for the Github actions case, the IP address range used is the same for Azure cloud.
I can figure it out here for all Github ecosystem, and I can get a quite extensive IP addresses array list for Github actions by doing this request
curl \
-H "Accept: application/vnd.github.v3+json" \
https://api.github.com/meta
The IP address shown in the error is changing every time, I could add all the IP ranges on Atlas API access list via API (the CIDR blocks are 1639 items), but again, not sure why this situation comes up now and not before when it was working well.