S6 EDGE PLUS how to write cert

Waiting ADB device… OK
Reading phone info…
Model: SM-G928F
Android version: 5.1.1
Product code: SM-G928FZDAXFV
Phone version: G928FXXS2AOK3
PDA version: G928FXXS2AOK9
CSC version: G928FVFG2AOJ3
CSC country code: South Africa
CSC sales code: XFV
HW version: MP 0.500
Phone S/N:
Modem board: SHANNON333
RF cal date: 20150814
Checking Super user right… true
Initialization AT RIL… OK
Checking for compatible phone and cert
Phone KEY ID: 0784
Checking certificate file… OK
KEY ID: 0784
Initializating zTool… OK
Running zTool, please wait… error (7.7.8)
Done with Samsung Tool PRO v.23.9

how can do it,please help me