I would guess you are using exim on port 26 and it indicates in the alert you received that chkservd cannot connect to 127.0.0.1:26
The chkservd process attempts to connect to “127.0.0.1:26” in order to validate that this service is functioning. If you blocked connections with iptables or the “Host Access Control” interface in WHM, this failure may be a false positive.
To resolve this issue, either open the firewall to allow connections as the root user to “127.0.0.1:26” or disable checks for this service in WHM’s “Service Manager” interface
As the notification states - the first and most important thing to ascertain is whether these are false positives, or if the services were actually down......in which case you may have much bigger problems
Assuming the alerts are as a result of false positives, follow the instruction for each alert, one by one, until you have resolved the issues.
As far as the other services are concerned, you may need to revise firewall access from 127.0.0.1 to the ports that they listen on. For full information on ports that should be configured please see
How to Configure Your Firewall for cPanel Services - cPanel Knowledge Base - cPanel Documentation
Additional information on the TailWatch / chkservd services are available at
TailWatch - cPanel Knowledge Base - cPanel Documentation
You may also want to check that access by localhost to any of the monitored services have not been blocked by Host Access Control entries.
