Backoffice gives 403 when website runs in IIS, but not visual studio

Anyone seen this before? Published umbraco (15) to IIS, site loads ok. But going into /umbraco redirects into 403 /umbraco/login?. this is with https disabled, since it’s not up yet.

Runs perfectly fine in visual studio.

Does your Program.cs have the app.UseHttpsRedirection() in it? If so, that would be forcing a redirect to https.

When spinning up the project in VS IIS Express it will auto generate an https certificate and use it, which could explain the discrepancy. But not enough information to know if this is the case here.