Message extension based on API throwing "Unable to reach app. Please try again."

Copper Contributor



I have built a new message extension based on OpenAPI spec using Teams tool kit. I then launch it in dev for testing (F5). I can see the app and invoke it but when I give input parameter it throws "Unable to reach app. Please try again." Screenshot below.


I then try to build another one by following the step by step guide in the link below. Its same result again. I can access the app but when I give input value it throws "Unable to reach app. Please try again."




This is my first ever message extension. I am not sure what I am missing. Appreciate any help to resolve this.




5 Replies
Hello @SatBhat - Thanks for raising your query.
We will look into it and let you know the updates.

Hello @SatBhat - We have followed all the steps mentioned in this documentation and it is working fine for us:


Please verify if you have provisioned your application before debugging the code.
Please refer this issue:

MicrosoftTeams-image (33).png

Hi @ChetanSharma-msft thanks for looking into this.
I figured out that I had to manually click on Provision. Without that my message extension wasn’t getting listed at all. Once I started manually provisioning I started seeing the message extension in the list, but was getting that 'Unable to reach...' error
1) What change you had to do to resolve that issue of getting NA/NA in search result?
2) When I changed the openapi:3.0.1 to 3.1.0 I was getting below error while provisioning.

[m365.UnhandledError]: An unexpected error has occurred while performing the M365 task. {"message":"Request failed with status code 400","detail":"{\"error\":{\"code\":\"BadRequest\",\"message\":\"OpenAPI specification version '3.1.0' is not supported.\"}}","tracingId":"00-508e6fd14f9aebfd1f6b96273433def0-8d2e04ed3b95ed46-00"}

So stayed with 3.0.1 although it was highlighting error around this version. Could that be the cause for the issue "Unable to reach app. Please try again."

My teams tool kit version is 5.4.1

3) You ok to share .zip file that was produced when you followed below step by step guide? I would like to compare it with my set of files

Once again thanks for your help with this.


Hello @SatBhat - Please find below comments on your queries:
1) Regarding NA/NA => We are getting this because of the configuration done in the "previewCardTemplate" like below and we are not getting top level values in the result of API call:

Even if we are getting NA/NA in search result, if you select and post it in the Teams, you will be able to see the actual results.

You may need to update the logic and map the data if we will be able to get those values:

"previewCardTemplate": {
    "title": "${if(name, name, 'N/A')}",
    "subtitle": "${if(opentools_url, opentools_url, 'N/A')}"

2) Please use same 3.0.1 version rather than 3.1.0. Also, I am also using same version and getting proper results:

3) Your zip package should contain all of below files:

Please find below JSON file:

    "$schema": "",
    "manifestVersion": "devPreview",
    "version": "1.0.0",
    "id": "55048865-a475-46c3-b91d-649c10f0ff1a",
    "packageName": "",
    "developer": {
        "name": "Teams App, Inc.",
        "websiteUrl": "",
        "privacyUrl": "",
        "termsOfUseUrl": ""
    "icons": {
        "color": "color.png",
        "outline": "outline.png"
    "name": {
        "short": "api-medev",
        "full": "Full name for api-me"
    "description": {
        "short": "OpenTools Plugin",
        "full": "A plugin that allows the user to find the most appropriate AI tools for their use cases, with their pricing information."
    "accentColor": "#FFFFFF",
    "composeExtensions": [
            "composeExtensionType": "apiBased",
            "apiSpecificationFile": "apiSpecificationFiles/openapi.yaml",
            "commands": [
                    "context": [
                    "type": "query",
                    "title": "Search for AI Tools",
                    "id": "searchTools",
                    "parameters": [
                            "name": "search",
                            "title": "Search",
                            "description": "Used to search for AI tools by their category based on the keywords. For example, ?search=\"tool to create music\" will give tools"
                    "description": "",
                    "apiResponseRenderingTemplateFile": "responseTemplates/searchTools.json"
    "permissions": [
    "validDomains": []
Thank you @ChetanSharma-msft for your help with this. It is now working for me. Once the demo version worked I could amend my code to align with demo version and make it work.
I had path name in the URL (for example - instead of just which is why I was getting Unable to reach error with my messaging extension. Once I removed this it started working.

Thanks once again :)