I have had a glowforge for about 4 years now and never herd of this so i had to look it up.
If you have a Glowforge Pro, the Safety Interlock is that little staple in a circular fitting just above the power switch on the back. If it works itself loose it will break the connection and show that interlock message. Check to see that it is fully inserted.
They say to also check the ribbon connection to the Head of the unit, but you most likely did some research on your own about this , and I have a bad feeling you might have to send your unit back Sadly .
The pin is a low-voltage connection, used to bypass a simple switch that uses an industry-standard connection.
It’s hard for it to “break”, it’s more likely the wires from the socket that the pin drops into have detached from the circuit board, or broken somehow. It’s not something you can fix, unless you are really handy and your machine is out of warranty.
It’s an obscure one for me and I’m at a total loss how it’s happened. I had not come across other users having this when reading up prior to buying my unit, but I have come across another user who has a new unit experiencing the same issue as me.
I’ve checked the small fitting and ribbon cables but getting the same results. So far, all those I’ve found have had to have their units replaced by support.
Thankfully, it under warranty but it sucks to be down when I needed it. Attaching photos submitted with the support ticket below.