Question iMac doesn't detect Samsung monitor after moving them to a new location ?

[RICSTIX]

I have an iMac with an external Samsung C27 F591 27" monitor and all was working well until I disconnected and moved the set up to a new location. Now the iMac isn't seeing the Samsung monitor.

A cable is plugged into the DP In connector on the monitor and a USB C on the iMac. Can someone please tell me the settings I need to input on the monitor please?

 

[helpstar]

Did you connect the USB-C into the correct port? Not all USB-C ports might support DP
try using a USB port with a flash symbol

https://help.apple.com/assets/6244BE6AE83C5279F505C060/6244BE75E83C5279F505C0C5/de_DE/de8ec66c3f75918daf48414d7d6cd500.png