Strange Problem

[BasilF]

I have Pro Tools 2019 (Windows). All of a sudden, on any tune, when I press play, the stop and play buttons blink for 15-20 seconds and then stop. Sometimes, when I first go to a tune, I can click play and it plays but the second I stop it and hit play again, the blinking happens again. Any ideas?

[BScout]

Pro Tools is having a hard time communicating with your audio interface. That's what that symptom usually is.
I'd check all your connections to the interface.

[albee1952]

More ideas:
1-restart the session(works for me whenever this happens)
2-make sure you don't accidentally put PT into "Wait for Midi"(F11, which is right next to F12 and many of us Windows users will use F12 to start recording).
3-trashing prefs is always worth a try for any odd behavior