Formula result not being displayed

[FLICK85]

Hello
I am hoping that this is very straightforward however has me stumped. I have a vlookup formula to return a result on a different sheet within the same workbook. Formula is:
=(VLOOKUP(A12,'Production Summary - DEC 19'!A:GG,172,FALSE))
The actual data should return 1000 but is actually returning 0. Before you say its because of the number stored as text or alike I have reviewed the reviewed the result in the function argument and it says the formula result is 1000. Why is it not displaying this?
Please help

 

[FormR]

What do these formulas return when put in a spare cell and changing the A1 cell reference to the address of the cell that contains your VLOOKUP() function?

=A1=1000
=A1=0

Do you have any circular references?
Is calculation set to automatic?

 

[FLICK85]

1. ='Production Summary - DEC 19'!FP11=1000 returns TRUE

2. ='Production Summary - DEC 19'!FP11=0 returns FALSE

Circular references: Yes apparently so. I have tried copying and paste special: value. It wont allow it due to there being circular references.

Calculation is set to automatic.

 

[FormR]

Circular references: Yes apparently so.

That'll be the problem then, you'll need to find and remove them. You can use the "Error Checking" drop down on the "Formulas" tab to help locate them.

 

[FLICK85]

Resolved - thank you to everyone that has taken the time to assist have a great day!