Teams Tab App displays "chromewebdata/" instead of HTML file



I'm having trouble loading a custom tab in Teams on an external web server. When I use the DevTools, I can see that the default index.html file is not opened. I instead see "extension-tab-frame (chromewebdata/)". Do you have any idea why?



When I use ngrok to host the exact same Teams tab app on localhost, it works fine. It displays the file "index.html":



Do I need to configure something in my manifest.json file or in the Azure AD to allow an a Teams tab app to be hosted on an external web server? I can display the index.html file in a browser so there does not appear to be anyting wrong with the web server. (I'm using Tomcat with TLS on port 443)

Here is what what my Teams tab app manifest.json file looks like:

    "developer": {
    "icons": {
    "name": {
        "short""GcTest App",
        "full""GcTest App for Microsoft Teams"
    "description": {
        "short""App for Microsoft Teams",
        "full""This app provides an innterface to make GENCom voice calls from within Microsoft Teams."
    "staticTabs": [
            "name""Contact List",
            "scopes": [
    "permissions": [
    "validDomains": [




3 Replies

@George71 , I see that valid domains is an ip address.You need to have a valid domain to make this work. 

@Manish-MSFT, does the the domain need to be visible by the Azure AD as well? Right now there is no domain defined for the IP address I am using so I am wondering if I can just add an entry in my Windows host file C:\Windows\System32\drivers\etc\hosts. If I do this, it won't be visible to the Azure AD.  Does it matter?

@George71 , Sorry for late response from our side, In order for webpages to load you need to have valid domain mentioned in manifest. In manifest given above I see there is an IP address entered in place of vaild domains.