Thank you for the prompt response.
We need to clarify the information you provided regarding the removal of the Excel for iOS app. Did you sign out your Microsoft account from the other Microsoft apps that are installed on your iPad before restarting the device? If you didn't, please try
to remove your Microsoft account first before restarting the device, and then install back Excel for iOS.
If the issue still continues even after going through those steps, we encourage you to submit a feedback about the issue on
Excel for iPad & iPhone (iOS) - UserVoice. Please make sure to sign in using a valid email account so you can monitor the status
of your feedback. Excel for iPad & iPhone (iOS) - UserVoice is managed by the
Excel Team that reviews customer's feedback and suggestions.
Should you need further help with other concerns in the future, you're always welcome to post back.