an error occurred when i do the Back to back test, in the following are the error described

when i do the SIL test(Back to back) using the model reference block by modifying the simulation mode,

an error occurred:

An error occurred ('Simulink:modelReference:TargetUpdateError') when calling 'sim':

Unable to update models referenced by 'iDaDesFfd_Reference_Harness'.

Error(s) encountered while building "rtwshared"

[qiang tian]

this problem has bothered me for a long time ,i hope sb can help me ,thanks very much!!