One of my fly instances consistently cannot connect to www.googleapis.com.
Bad instance:
# wget https://www.googleapis.com/oauth2/v4/token
Connecting to www.googleapis.com ([2a00:1450:4007:80e::200a]:443)
wget: can't connect to remote host: Operation timed out
Good instance:
# wget https://www.googleapis.com/oauth2/v4/token
Connecting to www.googleapis.com ([2607:f8b0:4004:c09::5f]:443)
wget: server returned error: HTTP/1.1 404 Not Found
Most likely the bad instance IP address is banned by google for some reason. You can connect to other services to check if it is Google-specific, and use dedicated IP to fix it.
Does any ipv6 work from the bad instance or is it only googleapis.com? It could be a routing issue from one of our hosts. Can you let me know your app name(s)?