This error message usually occurs when you have exceeded the maximum number of arguments that Excel can handle in a single formula. The maximum number of arguments that Excel can handle depends on the version of Excel you are using.

To resolve this issue, you can try the following steps:

1. Break down your formula into smaller parts. Instead of trying to sum all the numbers in one formula, try to sum them in smaller groups. For example, if you are trying to sum 10 numbers, try to sum them in groups of 5.
   
2. Use helper cells. You can use helper cells to calculate intermediate results and then use these results in your final formula. This can help you avoid exceeding the maximum number of arguments.
   
3. Upgrade your version of Excel. If you are using an older version of Excel, you may want to consider upgrading to a newer version that can handle more arguments.
   
4. Use a different function. If you are using the SUM function and are still having issues, you can try using a different function such as SUMIF or SUMIFS.