Need help on this formula. Need cell I21 to find the most occuring issue if "'1st QRT Weld'!A2:50" equals "F21". Cell that the issues are in are on "1st QRT Weld'!F2:F50"

This is the formula that i have to find the most occuring in cell "1st QRT Weld'!E2:50"

=INDEX('1st QTR Weld'!F2:F50,MATCH(MAX(COUNTIF('1st QTR Weld'!F2:F50,'1st QTR Weld'!F2:F50)),COUNTIF('1st QTR Weld'!F2:F50,'1st QTR Weld'!F2:F50),0))) (Array Formula)

But need it to only find the most occuring issue if '1st QRT Weld'!A2:50" equals "F21".

This is what i tryed but coming up "0"

=COUNTIF('1st QTR Weld'!C:C,'1st QTR DATA'!F21INDEX('1st QTR Weld'!E2:E50,MATCH(MAX(COUNTIF('1st QTR Weld'!E2:E50,'1st QTR Weld'!E2:E50)),COUNTIF('1st QTR Weld'!E2:E50,'1st QTR Weld'!E2:E50),0)))

Any suggenstions

Thank you