Hi DaShakkaKhan and welcome to ROG.

A couple of things will give a temperature over error. Assuming you have all connections from PSU to MB are correctly installed!!

You will have to remove your CPU, as this is a common cause, where you have a poor thermal contact with the Water cooler.

It is always best to benchtest outside your case initially, to avoid having to do this.

It is also possible there is a faulty sensor on the MB, less likely.

When you remove the CPU, clean the surfaces well with alcohol and apply only a small pea sized amount of Arctic Silver in the middle of the heat sink.
You only need enough to spread a very thin layer when under compression, Tighten down a little at a time from each corner and don't over tighten.

It is difficult to determine the actual flow of the H100 being a closed loop system, But under load you can feel the heat being carried away from the CPU when you carefully hold the exit tube. I have not encountered a failure yet unless, you do not cable up correctly.

Also, depending at what point you encountered the error, you may encounter problems when you boot into windows if indeed that is where the error occurred.

When starting up next, observe the Qcode readout should it fail transition into ACPI and report back with the readout.

Should you make a successful transition into your OS, then you can gather more specific readings.