I keep getting Syntax errors, can someone help me please?

Hi wbarnes ,

In DAX, string outputs in a measure must be returned as a DAX expression, not as comments (i.e., you can’t use -- for comments inside the formula). Also, "General Number" is not a valid format string for FORMAT—use "#" or just wrap the number in FORMAT without a format string.

Provider ID =
VAR ProviderID = 
    LOOKUPVALUE(
        'Provider Lookup'[Provider ID],
        'Provider Lookup'[Provider Name],
        'Code Stroke DDR'[Who provided Telestroke Service]
    )
RETURN
IF(
    ISBLANK(ProviderID),
    "No ID",
    FORMAT(ProviderID, "")
)