Cross sheet countifs

Hi,

Attempting cross sheet counts for totals by month and year the number of times "x" appears, in the example below I selected "DTS" from the other sheet. I can get the total column count from the other sheet with =COUNTIFS({Container COMPLETED Range 2}, "DTS") but when I add all in italic below I get #Unparseable. I have also tried with AND( before IFERROR and get #Incorrect Argument Set.

Range 2, is my other sheet column that contains "DTS"

Range 5, is my date column in the same sheet.

=COUNTIFS({Container COMPLETED Range 2}, "DTS", ({Container COMPLETED Range 5}), IFERROR(YEAR(@cell), 0) = 2020, IFERROR(MONTH(@cell), 0) = 1))

Help - cheers.