Whmcs Cyberpanel Module has lots of problems and it does not support newly created ALS
as well as a PORT change to 8090 To 2087 doesn’t support it. I had opened both ports in my Cyberpanel.
Install whmcs module after changing the port or try it in default port 8090 for now and see if it still has issues.
Many users already using whmcs and didnt reported any major issues. Are you having a valid license for whmcs?