G & L Indonesian Trib Bass Truss Rod adjustment. Please help

Hi, I just recently got my L 2000 bass from Thomann and the action is way too low. I think the neck is too flat and would like to loosen the trus rod but I found a link here on this forum and it says to use a 4mm allen hexagon wrench. I tried this and it does not work. Is the 4mm still the adjustment tool for this model of G & L bass or is another tool what I need?

thank you in advance

Hi, I just recently got my L 2000 bass from Thomann and the action is way too low. I think the neck is too flat and would like to loosen the trus rod but I found a link here on this forum and it says to use a 4mm allen hexagon wrench. I tried this and it does not work. Is the 4mm still the adjustment tool for this model of G & L bass or is another tool what I need?

thank you in advance

Yes, the 4mm allen wrench should be used for the trussrod adjustment.
Did you get a set of wrenches which came with the bass?
What exactly is not working? Perhaps post some photos of the access to the trussrod nut.
What is the first four digits of the serial number, which is the build YY/MM of the bass.

See this sheet for adjusting the trussrod:Double Action Truss Rod Instruction Sheet (2016).