In v4 the debugger is enabled by default.
If you check your log files you will find the debugger password.
It looks like the debugger is disabled for your license. I suggest to contact the mendix Support team to help you.
According to the Mendix How to it should be there: https://docs.mendix.com/howto7/monitoring-troubleshooting/debug-microflows-remotely#31-enabling-debugging-in-the-cloud.