There are numerous factors on why the connection stop working. Here are a few things to check.
Try running the following command on the remote server
perl /etc/csf/csf.pl -r
and if you get result similar to
Can't locate YAML/Tiny.pm in @INC (@INC contains: /usr/local/csf/lib /usr/local/cpanel /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at /usr/local/csf/lib/ConfigServer/CloudFlare.pm line 41. Compilation failed in require at /etc/csf/csf.pl line 202.
then you just need to run the following command to fix the missing dependency.
If you don't get the error when running the first command, then make sure there is a CRONJOB installed on the remote server.