“401 Unauthorized” error during form data save

  Issue:

When you try to save a new form item, you encounter a “401 Unauthorized” error

  Resolution:

Option1: If you are using location-based policy in SharePoint Online, disable it.

Option 2: Even though Microsoft claims that location-based policy might not be the best solution when using any provider-hosted SharePoint Apps you can apply a workaround. You need to include the IP Addresses that Azure websites are using in you location-based policy white list:

1. Download the text file with list of IP addresses used by Azure websites (this list is taken from the official Microsoft Azure Datacenter IP Ranges document).
2. Navigate to Access Policy Settings in Microsoft 365.
3. Press the “Edit” button to edit the IP addresses white list.
4. Paste the content of the downloaded file into a textfield that will appear (each address should be placed in a separate line).
5. Press the save button (on the very bottom of the page).
6. Wait until the policy changes get applied on the tenant. It might take up to 20 minutes.