Hi Terri Cortes,
Thanks for your post in Microsoft Community.
This is a recent hot issue. Have you been using any web service-based functions in your workbook, such as WEBSERVICE or STOCKHISTORY? Recently, many users have reported the same error message, and the common factor is the use of similar web service functions. We would like to confirm this with you.
Additionally, what is your Office version? You can check this by opening the Excel application > File > Account. This issue could be influenced by a version update patch. We need to gather some information to report to the development team.
The support team is aware of this issue and is currently investigating and writing a report. Meanwhile, we are working with users to explore some temporary solutions.
Below is a potential solution that has worked for a small number of users; you might want to give it a try:
Open the Excel application > File > Options > Advanced > scroll down to find and disable 'Enable multi-threaded calculation'.

This issue may be the result of inconsistencies between the multithreaded processor and Excel itself.
I hope my explanation helps you understand the current situation regarding the issue you are facing, and I look forward to your reply!
Best Regards,
Thomas C - MSFT | Microsoft Community Support Specialist