A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hi, @Matt May
Does this happen only in Excel, or also in Word and other Office apps?
Please also check whether your Microsoft 365 subscription or Office license appears here: https://account.microsoft.com/services
For now, close all Office apps, restart the PC, then open Excel and try signing in again.
Also, can you sign in and use Excel on the web at https://www.office.com, or do you get the same error there?