You may see that clients are routinely being logged out of cPanel or WHM interfaces, and the message "Your IP Address Has Changed" will display.
This issue is caused when a user logs in, and then the IP address that they are accessing cPanel from changes.
This change is detected by a setting named 'Cookie IP Validation'.
WHM: Home -> Server Configuration -> Tweak Settings
Option: Cookie IP validation
Scroll down for 'Cookie IP validation' for more information.
In Tweak Settings, by default, this setting is set to 'strict'.
Changing the value to 'loose' should allow them to be connected.
If you continue to see users being disconnected from cPanel or WHM, change the value to 'disable' to stop it entirely.