Okuma Alarm-A 8502 Unable to G21

Okuma Alarm-A 8502 Unable to G21
Axis movement to the tool change position G21 is issued without satisfying the conditions for executing the command.
(G21command is also issued in execution of ATC macro command G171 and M421.)

Code
1->A turret index state has resulted in the following state.
HP=1 …. Turret is not indexed to ATC position.

HP=2 …. Turret is not indexed to ATC position.

HP=3 …. T1 is not indexed to ATC position on LU45-MATC-Y turret.

Probable Faulty Locations
1)With HP = 1, the L-tool mounted station is indexed to the tool change position. With HP = 2, the facing tool mounted station is indexed to the tool change position.(With MacTurn, M-tool mounted station is indexed to the tool change position.)