Page not found 404 on Default.aspx
Why do you receive a 404 when trying to visit Default.aspx on your SharePoint Site ( among other multiple reasons) ?
Answer ( among other potential answers ) :)
The site might reside at the root of a Wildcard inclusion managed path.
EX:
Webapplication https://SharePoint
Managed Path at /ManPath/
The Default page at https://SharePoint/ManPath/Default.aspx
When you try to access the site, you receive a 404 (Page not found)
Why
By design
Solution
Remove the managed path through UI or powershell
$wa = Get-SPWebApplication -identity https://SharePoint
$wa.Prefixes
$wa.Prefixes.Delete("ManPath")
$wa.Update()
How do you end-up in this ?
Well, by creating a managed path at the same URL as your newly created TeamSite