Problem in using solver and VBA to maximise equation

Im trying to maximise the likelihood function for the JD model for estimating the parameters by using solver. But i got a warning message "Solver encountered an error value in a target of constraint cell". Im a beginner in VBA. Anyone here can help me to fix this issue?
The data of xst I get from the datasheet, and theta includes 5 parameters that I want to estimate.

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