This app is blocked message, although I added the extension to all users in the domain

[stephano-gabriel]

[nileshtrivedi]

Got the same error.

[jmccarron212]

It needs to be set as a trusted app. Here's what worked for me.

1. Navigate to your Google Workspace Admin Dashboard
2. Search "API controls" with the search bar on the top and select the option nested under "Security"
3. Click "Manage Third-Party App Access" on the right side of the page
4. At the top of the "Configured Apps" list, click on the "Add app" drop down and select "OAuth App Name Or Client ID"
5. Search for the name "What-If Analysis"
6. Select the OAuth Client ID 430660745752-o2krqqotjie8sd5c5pvtpjt1u9kcj9th.apps.googleusercontent.com
7. Click Select
8. Select the appropriate scope
9. Click Continue
10. Select "Trusted"
11. Click Continue
12. Review the changes and if everything looks good click Finished

I then quit and relaunched Chrome, loaded up a sheet and the What-If add in worked after I was asked to authenticate which I did successfully.