Audio output stopped suddenly

I am still fairly new to use Permiere Pro but I have created several video projects in the last year and a half.  I have muddled along and been able to create videos for personal use but I am definitely not yet a pro.  Well, this evening I had been editing a 1 hour long video and had edited down to just about 45 minutes.  All had been going well.  No problems with clipping or deleting small parts of the video with the connected audio.  I was almost done with the editing as I was working on this project tonight when suddenly I could not hear the audio in the playback.   I must have hit some button or clicked on something but I have no idea what it might have been.  I had been using my space bar to move through the timeline and was using "L" to go through it quickly for the ensure all was done correctly.  Again, all was going well when I just all of a sudden could not hear the audio in the playback.  I closed the project without saving  it and opened a different project.  No problem.  I can hear the audio perfectly in that other project.  I also tried just listening to YouTube on my computer to test my audio outside of Premiere Pro but again, I had no problem with the audio.  But when I open the project that I had been working on, again I had no audio.  I believe I have the latest version of Adobe Premiere Pro and I am working on a fairly new Dell Windows 11 desktop computer.  I would appreciate any guidance or assistance anyone can give me.  Thank you.  Armando