Commonly on CGNAT your connection will be assigned a range of source ports. The web server can see that all your connections have a source port number between 1

Commonly on CGNAT your connection will be assigned a range of source ports. The web server can see that all your connections have a source port number between 10,000 and 20,000, for instance, so they block new connections in that range. This would not directly target you (unless there's only 6 customers per NATted IP) but it does reduce the blast radius.