Thank you @WHMCS Peter because help. but now has other errors. I'm really disappointing with Whmcs 7.5.1 this. Update for the system of the running system is not stable. new error as this
Welcome to WHMCS.Community anhtuan! We're glad you're here please take some time to familiarise yourself with the Community Rules & Guidelines and take a moment to introduce yourself to other WHMCS.Community members in the Introduce Yourself Board.