If spell check isn't working properly, try the following steps:
Check your internet connection: Spelling and grammar checkers require an internet connection to work properly. Make sure you have a stable internet connection before troubleshooting any further.
Check your software version: If you are using an older version of Microsoft Word, the spell check feature may not be available. Make sure you have the latest version of the software installed.
Make sure the feature is turned on: In some versions of Word, spell check can be turned off. To turn it back on, open the tools menu and select “Options”. In the “Options” window, select the “Spelling & Grammar” tab and make sure the check box next to the feature is checked.
Update your dictionary: If none of the above steps have worked, you may need to update your dictionary. Visit Microsoft's website [1] and navigate to the download page for the latest version of the dictionary you need. Then, download and install the file on your computer.
Hopefully these steps have helped you get spell check to work again. If you're still having issues, you may need to seek additional help from a technician.
[1]https://support.microsoft.com/en-us/office/download-and-install-or-reinstall-office-365-or-office-2019-on-a-pc-or-mac-4414eaaf-0478-48be-9c42-23adc4716658