If you're having trouble getting AutoFill to work as expected in Microsoft Excel, there are a few things you can check to troubleshoot the issue.

Check Your Data

First, take a look at the data you're trying to use with AutoFill. Make sure it's all in the correct format and that there are no blank cells or cells with invalid data. If your data is clean and well-organized, AutoFill should work as expected.

Check Your Settings

Next, check your AutoFill settings to make sure they're configured correctly. To do this, go to File > Options > Advanced and scroll down to the Editing options section. Make sure the Enable fill handle and cell drag-and-drop option is selected.

If this option is disabled, AutoFill will not work. You can also try changing the AutoFill options. To do this, go to File > Options > Advanced, scroll down to the Editing options section, and click on the AutoFill Options button. From here, you can select different options for how AutoFill works.