Nothing. It's outbound 443 to authenticate.
That really reinforces you have an ISP blocking/doing something if you can't connect.
This means you are being blocked by something (firewall/AV/ISP). If you can connect via Cloudflare Warp, that would rule out the machine back to the ISP.
If this fails, there is not much you can do:
curl https://oauth2.googleapis.com/token -vvv
* Trying 142.251.35.170:443...
* TCP_NODELAY set
* Connected to oauth2.googleapis.com (142.251.35.170) port 443 (#0)
You may want to check your DNS as well as your oauth request is resolving to something I'd say is a bit strange.
13.127.247.216 - Find IP Address - Lookup and locate an ip address (findip-address.com)
Which I also cannot connect to:
telnet 13.127.247.216 443
Trying 13.127.247.216...
I get:
host oauth2.googleapis.com
oauth2.googleapis.com has address 142.251.35.170
oauth2.googleapis.com has IPv6 address 2607:f8b0:4006:80d::200a
But Google does do Geo load balancing as well.
I tried a few DNS servers and get the same IP back relatively speaking:
nslookup
> server 1.1.1.1
Default server: 1.1.1.1
Address: 1.1.1.1#53
> oauth2.googleapis.com
Server: 1.1.1.1
Address: 1.1.1.1#53
Non-authoritative answer:
Name: oauth2.googleapis.com
Address: 142.250.72.106
Name: oauth2.googleapis.com
Address: 2607:f8b0:4006:823::200a
> server 8.8.8.8
Default server: 8.8.8.8
Address: 8.8.8.8#53
> oauth2.googleapis.com
Server: 8.8.8.8
Address: 8.8.8.8#53
Non-authoritative answer:
Name: oauth2.googleapis.com
Address: 142.251.32.106
Name: oauth2.googleapis.com
Address: 2607:f8b0:4006:809::200a
> server 9.9.9.9
Default server: 9.9.9.9
Address: 9.9.9.9#53
> oauth2.googleapis.com
Server: 9.9.9.9
Address: 9.9.9.9#53
Non-authoritative answer:
Name: oauth2.googleapis.com
Address: 142.250.64.202
Name: oauth2.googleapis.com
Address: 2607:f8b0:4008:807::200a
>