Some time (not sure how long) after I set up my Cloud Firewall, I discovered that the built-in iptables firewall in my CentOS droplet has stopped working. I have this message in diagnostics:

iptables v1.4.21: can’t initialize iptables table `filter’: Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

Is this typical? I upgraded the kernel about two weeks after the SPECTRE/etc. reports came out, not sure if that is part of the scenario either.