Store Envelope of AQB

I am using AQB to calculate the non-linear stresses (NSTR) of beam elements. I would like to store the envelope of the AQB results in 1 Load Case. Usually I use the command “COMB GMAX LCST 98” for this, but it does not seem to work as I am getting the following error:

+++++ error no. 2053 in program AQBEI ; input line: 14
It is not possible to store a new stiffness in the database
for combined load cases

This is the code that I am using:

+PROG AQB urs:53
HEAD PIERS - NON LINEAR STRESS - SLS RARE

CTRL REIN FIX

BEAM GRP #GRP_Piers
LC (100 120 1)

COMB GMAX LCST 98 TITL ‘Piers_SLS_Rare_Max’
COMB GMIN LCST 99 TITL ‘Piers_SLS_Rare_Min’

NSTR SN KSV EL KSB EL CRAC NO CHKR 0.8*#Fyk_Reinforcem[MPa] CHKC 0.60*#Fck_Conc_Piers[MPa]

ECHO FULL FULL

END

Use nstr serv instead of nstr sn