Here we go, thank you for your helpPlease post a log with your issue! Here's how...
OBS Studio creates a log file each time you run it which contains very useful diagnostic information. Without a log file, it's much harder for any support volunteers to figure out problems and your post may be ignored. To upload a log file, go to the Help menu > Log Files > Upload Last Log...obsproject.com
I have three monitors connected but I choose only one at a time when I want to record and I also checked the setting it is only 1080 PNVENC supports up to 4096x4096. You are trying to use 14400x900, typo?