Showing intranet sites (Sharepoint) inside teams client

Hello Fredeids, 

1. The redirection to an external browser happens because some SharePoint links are not optimized for embedding in Teams. This behavior is controlled by SharePoint's security policies and Teams' webview limitations.

• Solution: Ensure that all links in your navigation bar are "Teams-friendly." Use the ?web=1 query parameter in your SharePoint URLs to force them to open in Teams. For example:This parameter ensures that the content is rendered in the Teams webview instead of redirecting to the browser.
  https://yourtenant.sharepoint.com/sites/YourSite?web=1
• Manifest Configuration: Double-check your app manifest to ensure the webContentUrl is correctly set and includes the ?web=1 or ?app=portals parameter.
  Example: "contentUrl": "https://yourtenant.sharepoint.com/sites/YourSite?app=portals"
• Navigation Links: For links in the navigation bar, ensure they are relative URLs or explicitly include the ?web=1 parameter.

2.Viva connection alternatives

• Viva Connections is designed to provide a seamless SharePoint experience in Teams. However, it currently supports only one default landing page per tenant.
• Workaround: Instead of using Viva Connections for all users, create separate Viva Connections apps for each user group (e.g., School A Student, School A Teacher). Each app can point to a different SharePoint home site. This requires creating multiple Viva Connections manifests and deploying them as separate Teams apps.

Document Link-
1.Integrate Teams Tab to SharePoint - Teams | Microsoft Learn
2.Overview: Viva Connections | Microsoft Learn