I'm working on a outlook web-addin. The addin works when in run it on local host, can see the addin in outlook. When the manifest file is validated with "npm run validate", it looks fine. But when I try to import the manifest file using Excel Web -> Insert -> Office Add-ins, I get "Your Addin manifest is not valid" error. could some on please guide how to identify the issue.
I'm planning to host the web UI in azure and install the manifest file on my team mate's machine to run some tests.
You need to use the target host application for sideloading the web add-in. In your case this is Outlook. Also you may consider deploying centralized, see Deploy add-ins in the Microsoft 365 admin center for more information.
You may also find the Deploy and install Outlook add-ins for testing article helpful.