How to solve?

[Nobre12]

[ script:vrp_nitro] Error loading script server.lua in resource vrp_nitro: [string "..."]:126: attempt to concatenate a nil value (local 'identifier') [ script:vrp_nitro] stack traceback: [ script:vrp_nitro] [string "..."]:126: in field 'getInterface' [ script:vrp_nitro] @vrp_nitro/server.lua:5: in main chunk