Teams incoming Webhook error 403 & 401

[st84]

Hello,

I'm setting up a Teams incoming webhook.

Work done so far:

1. Modify Teams app policy for admins to allow Incoming Webhook app
2. Create new channel in Teams 'webhook test'
3. Added incoming webhook connecter app to channel
   
   

Curl test:

Webhook message delivery failed with error: Microsoft Teams endpoint returned HTTP error 403 with ContextId tcid=0,server=msgapi-production-eus-azsc2-4-94,cv=uImyuiqzxxxxxxxbWzQ.001=2..

POST test:

...failed with status code 401(Unauthorized) and reason {"Message":"STI server YQBPRxxxxxxx9853 failed to process request...

Are there any more permissions/settings that need to be configured in order to get incoming webhook connectors working? Do I need to allow the Incoming Webhook app org wide, instead of just allowing a specific user group to add/manage incoming webhooks?

Cheers,

[#2]

@st84 Could it be that there is a firewall inbetween?

[#3]

The Teams documentation doesn't mention any ports needing to be opened for webhooks to work. Also, which firewall would/could that be anyways, if one is running/using Teams webapp? 

Shouldn't incoming webhooks work by default, provided the app is allowed and installed?

[#4]

Incoming Webhook has some problems since yesterday.