If you are connecting CRT and LCD with VGA and HDMI respectively, make sure to enable the EDID emulation for CRT is at the correct Device and Output choices. It usually happens when people forget to choose the correct Device or Output.
After that, you can use ArcadeOSD to double check the installed video modes for VGA output.
Open ArcadeOSD, if the window is on CRT with sync problem, press "2" to call it onto LCD, and check the video modes
Then, try different video modes to test if any modes work on CRT.
I experienced the similar problem, everything installed correctly, but the picture did not sync correctly due to unknown reason. It stood on a video mode which is out of sync with my CRT. I should manually switch to 15KHz video mode and keep it as desktop mode for one time. After that, everything works.
Good luck!