I allowed these ips on my server's firewall and it fixed the issue:
https://code.google.com/archive/p/recaptcha/wikis/FirewallsAndRecaptcha.wiki
{ 216.239.32.0/19, 64.233.160.0/19, 66.249.80.0/20, 72.14.192.0/18, 209.85.128.0/17, 66.102.0.0/20, 74.125.0.0/16, 64.18.0.0/20, 207.126.144.0/20, 173.194.0.0/16 }