In this configuration we use RouterBOARD wAP 2nD r2 with firmware v6.42.7
1. Create Layer 7
/ip firewall layer7-protocol
add name=Block-Youtube-App regexp=^.+(youtube.com|www.youtube.com|m.youtube.com|ytimg.com|s.ytimg.com|ytimg.l.google.com|youtube.l.google.com|i.google.com|googlevideo|youtu.be).*$
2. Create filter rule to Block Youtube App
/ip firewall filter
add action=drop chain=forward layer7-protocol=Block-Youtube-App src-address= 10.10.10.0/24
