Cannot play DVD.

If it is NTSC sometimes you need to change the TV to accept an NTSC signal but that may depend on how the player is connected to the TV. Do you have a PC with a DVD burner? If so rip it, change the format to PAL and burn to another disk.

Quite honestly, unless your TV and DVD player are more than 10 years old, I wouldn't worry about NTSC compatibility as pretty much all players and TV's support NTSC playback nowadays...

It's likely some setting that's not set how each other likes (timers or some eco mode or something) or as said above, a Region lock....

If you have Timers set on your DVD recorder, remove them, as they will be in PAL (our system) so the player locks into this expected mode... (a weird 'feature' of Panasonic DVD recorders)

you can delete all the timers, or switch over manually (but you will have to do this each time you switch between PAL and NTSC)

While the player is STOPPED, press and hold STOP and OPEN/CLOSE on the unit (not remote) for 5 seconds or so, the player should switch from PAL to NTSC or back.