Formula red dotted lines around cell.

It sounds like you are facing issues with Excel formulas, and it's crucial to troubleshoot and identify the problem. Here are some common reasons why formulas might not be working as expected:

1. **Delimiter Issue:**
- In some regions, Excel uses a semicolon (`;`) as the delimiter instead of a comma (`,`). If your Excel version uses semicolons, ensure that your formulas use the correct delimiter.

2. **Function Names:**
- Make sure you are using the correct function names and that they are spelled correctly. Excel functions are case-insensitive, but if there's a typo, the formula might not work.

3. **Cell References:**
- Check that your cell references are accurate. If you are referencing a range of cells, ensure the range is correct, and there are no typos in the reference.

4. **Data Types:**
- Ensure that the data types in your formula are compatible. For example, if you are performing a mathematical operation, make sure that the cells contain numerical data.

5. **Error Checking:**
- Excel usually provides error messages if there's an issue with the formula. If you don't see an error message, you might want to check the error checking options.
- Go to the "Formulas" tab.
- Click on "Error Checking" and then choose "Error Checking Options."
- Make sure that the "Enable background error checking" and "Error checking rules" options are selected.

6. **Cell Formatting:**
- Verify that the cells involved in the formula are formatted correctly. Sometimes, formatting issues can affect calculations.

7. **Calculation Settings:**
- Check your Excel calculation settings. Excel might be set to manual calculation mode, preventing formulas from updating automatically. You can change this setting in the Formulas tab under Calculation Options.

If the issue persists, it might be helpful to provide more details about the specific formula or function you are using, along with some sample data. This will allow for a more targeted and accurate solution to the problem.