Some datatypes not retrieved from Datastream

Hi

I am trying to fetch for instance the delta of a call option in Datastream. Unfortunately, this does not seem to be working.
fetch(d="DS_DB",link,c=l) SPX0316400C(DZ)
And it produced the following error message: "Database Error: number of observations does not match range in "fetch(d="DS_DB",link,c=l) SPX0316400C(DZ)".

Thanks in advance for looking into this.

Best regards
Rasmus

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