Usually if you have any problems with DC at the output of amplifier first step to check if all other components are OK is to disconnect output devices (drains and gates of both mosfets). Next connect both of 100 Ohm resistors connected to gates directly to output bus. Then you can check if output DC is close to zero volts. If you have audio generator and scope check if all amplifier and drivers are OK (do not connect any load). If that check will show OK you can connect back power transistors. If not check all transistors using multimeter in diode check mode. Also electrolytical capacitor C5 in feedback path if leaky can cause the problem. Before switching on the best way is to adjust RV1 to zero Ohm to avoid any problems with high idle current. Then you can adjust it by checking voltage drop in millivolts between sources of out transistors (the same value as in good amplifier). I do not like that in this circuit protection diodes are not connected directly to gates. This way they better protect gates since currrent would be limited by abovementioned resistors. If any of mosfets is gone it will usually show short between drain and source.