#N/A means a function (usually VLOOKUP, HLOOKUP, MATCH, or XLOOKUP) searched for a value and didn't find it. It also appears when a required argument is missing.
Trim and normalize
Wrap lookups in TRIM and ensure both sides are the same data type.
Force exact match
End VLOOKUP with FALSE (or use XLOOKUP, which is exact by default).
Show a friendly message
Wrap with IFERROR or IFNA to replace #N/A with text.
Wrap the formula in IFNA(formula, "") or IFERROR(formula, "").