If you're using Microsoft Excel and you find that the SUMIF function isn't recalculating automatically, there are a few things you can check to try and fix the issue.
First, make sure that the cells you're using in your SUMIF function are actually numerical values and not text strings. If they're text strings, the SUMIF function will not work correctly. You can convert them to numbers by selecting the cells and then going to the 'Data' tab on the ribbon and clicking 'Data Tools' > 'Text to Columns'.
Another thing to check is the cell references in your SUMIF function. Make sure they're all absolute references (with $ signs before both the column letter and row number) so that they don't change when you copy or move the formula around. If any of them are relative references, that could be why the SUMIF function isn't updating correctly.
Finally, if you're using an older version of Excel, it's possible that your SUMIF function is being affected by a bug that was fixed in more recent versions. To check if this is the case, try opening your workbook in a newer version of Excel and see if the SUMIF function starts working correctly. If it does, then you'll need to upgrade your version of Excel.