Thank you for the offer of support but I have sense figured out what was causing the issue, certain software will cause the backlighting to flicker when the refresh rate is set to 60.  I solved the problem by changing the refresh rate to 30 for the software that causes the problem then back again when done.
Hello all, I recently purchased a Dell S3221QS monitor that flickers only when my laptop is connected to the DisplayPort and only when a graphics application is running the foreground such as Stellarium.   I disabled DDC/CI but that did not fix the issue. I also uninstalled the Dell app that can control the monitor when the problem was not resolved. Any recommendations on how to fix the problem? Thanks,Chris
S3221QS, flickers only connected to DisplayPort