could do a DIY at home windows PC NTP server for all network equipment to go by. Forum post of how to do so is .... maybe a month back.
I run Home Assistant home automation software with the NTP server add-on. All network devices (Blue Iris machine, all cameras, all PC's, etc) run off this local server.
Or...you can hit 'sync with PC'. But I see you have the NVR, not PC. Hmm. I take it all back. Not sure how NVR & cameras talk to each other for time sync's.
my monitor psu failed so i did't get the monitor connected to the NVR, done some setup via the web browser, i know i can check a box and browse to each camera, ( we supply a different NVR, its all plug and play, everything gets synced. )