A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
You have a blank cell in C4 so it can't find the matching value. The value in C4 must match perfectly one of the values in the first column of the table array containing the names and team names.
If you want to insert the formulas before inserting the names then you need to handle the not found something like the following formula where it returns a zero length string if errors.
=IFERROR(VLOOKUP(C4,Teams!$A:$B,2,FALSE),"")