mktime(): It is not safe to rely on the system’s timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected ‘Asia/Hong_Kong’ for ‘HKT/8.0/no DST’ instead

Problem: mktime(): It is not safe to rely on the system’s timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected ‘Asia/Hong_Kong’ for ‘HKT/8.0/no DST’ instead

Solution:
Open php.ini and add this line:

date.timezone = “Asia/Hong_Kong”