=XLOOKUP(Customer,Summary_Aging[Customer '#],Summary_Aging[Telephone])

Hello LaQuintin Holloway, welcome to Microsoft Q&A forum.

Your formula is structured correctly, but the #N/A error means Excel cannot find an exact match for the value you entered. To give you the most accurate help, could you share a screenshot of your data or upload a sample file?

In the meantime, here are some common causes you can check:

1. Data type mismatch

If the Customer value is stored as text and the Customer '# column is numeric (or vice versa), Excel will not match them and will return #N/A. This often happens when a number like 101 is mistyped or imported as text.

What to do:

• Check the format of the cell where you enter Customer and the Customer '# column in your table. Both should be Number if account numbers are numeric.
• If you find text values, convert them to numbers. You can just change the format to Number and re-enter the value or force conversion in the formula:

=XLOOKUP(VALUE(Customer), Summary_Aging[Customer '#], Summary_Aging[Telephone], "Not Found")

see: Convert numbers stored as text to numbers in Excel

2. Value not found

If the account number does not exist in the Customer '# column, #N/A is expected. You can add a fallback argument (the fourth argument in XLOOKUP) so it returns a message instead of #N/A:

=XLOOKUP(Customer, Summary_Aging[Customer '#], Summary_Aging[Telephone], "Not Found")

Other things to check include extra spaces or hidden characters.

Please share the screenshot or file so we can confirm the exact cause and provide a precise solution. Until then, these quick checks should help you troubleshoot most cases.

Warm regards,

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