When you disable it, routerOS will function only as an NTP consumer. Ok if you want to use correct clock for logging etcetera. The devices in your network really should use exterior stratum three or four NTP servers just like the pool.ntp.org clusters anyway. Checking the WinBox approach in Action https://sethdxnbs.blogchaat.com/35367521/5-essential-elements-for-https-www-winbox88trust1-asia-login