Issue: second user cannot log into Excel Add-in using Single Sign On (SSO)

You can can sign into the Excel Add-in using Single Sign On (SSO) after another user has signed in and out using SSO. To do so, you must enable the Clear Cache setting in the Trusted Add-in catalog options.

1. Open Excel (if it isn't already open).

2. Navigate to File > Options > Trust Center > Trusted Add-in Catalogs.

3. Check Next time Office starts, clear all previously-started web add-ins cache.