new ATEM SDI Pro ISO Monitor issues

We replaced our ATEM Mini Pro Switcher with a ATEM Pro SDI ISO switcher. With the Mini Pro, we had 3 monitors running through a HDMI Splitter. No problems streaming 1920x1080 30fps.
We got the Pro SDI ISO for the dual outputs. We run two monitors ( small older cheap computer monitors) off one output through a splitter and the 3rd monitor off the second output. The 3rd monitor is a newer LG LED 27ML600 M/MN60T. The only way I can use this monitor is to stream 1080P 60fps. Any other setting gives an out of range message. I have tried cables, new SDI to HDMI converter, every setting on the monitor I could adjust. The monitor information says it's on 1920x1080P 60Hz.
The resolution settings on the monitor OSD is grayed out so I can't change it.

I want to stream 30fps not 60fps, do I need to downgrade the monitor to get the 3rd one to work?
Is there something different with the SDI ISO switcher's refresh rate?

you could use a decimator as a scan doubler to convert from 30fps to 60 (or whatever else)

Had the same Problem after Upgrading to Atem SDI, i had to switch to 1080p 50f. but i'e been experimenting with some monitors lately and it seems that Monitors with Adaptive Sync or Free Sync solde this Problem, They adapt the refresh rate to the SDI output , no need to change the Settings .

Let me know if this Helps !