There are a pair of Netgear S3300-52X switches which are not stacking.
The switches are directly connected by 1m of CAT6 cable between their 10G ports. The switches are both using the same version of the firmware.
Even after a restart, the Netgear switches are not auto-stacking and the switches do not show each other in the stack overview page. There are no other switches and the switches have not previously been stacked.
How can the switches be made to stack?