Node up 28.Sep.2021 14:56:12\n\nNormal] xxxxxx: Node up" }'
*   Trying 52.97.146.162:443...
* TCP_NODELAY set
* Connected to xxxxxxxx.webhook.office.com (52.97.146.162) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use h2
* Server certificate:
*  subject: C=US; ST=Washington; L=Redmond; O=Microsoft Corporation; CN=*.webhook.office.com
*  start date: May 12 00:00:00 2020 GMT
*  expire date: May 12 12:00:00 2022 GMT
*  subjectAltName: host "xxxxxx.webhook.office.com" matched cert's "*.webhook.office.com"
*  issuer: C=US; O=DigiCert Inc; CN=DigiCert Cloud Services CA-1
*  SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x56077e955e10)
> POST /webhookb2/xxxxxxx HTTP/2
> Host: xxxxx.webhook.office.com
> user-agent: curl/7.68.0
> accept: */*
> content-type: application/json
> content-length: 93
>
* We are completely uploaded and fine
* Connection state changed (MAX_CONCURRENT_STREAMS == 100)!
< HTTP/2 200
< cache-control: no-cache
< pragma: no-cache
< content-length: 1
< content-type: text/plain; charset=utf-8
< expires: -1
< server: Microsoft-IIS/10.0
< request-id: e043cd8f-7a80-4713-4620-fe2db9000165
< strict-transport-security: max-age=31536000; includeSubDomains; preload
< x-calculatedfetarget: CWLP265CU017.internal.outlook.com
< x-backendhttpstatus: 200
< x-feproxyinfo: CWLP265CA0401.GBRP265.PROD.OUTLOOK.COM
< x-calculatedbetarget: CWXP265MB1910.GBRP265.PROD.OUTLOOK.COM
< x-backendhttpstatus: 200
< x-aspnet-version: 4.0.30319
< x-cafeserver: CWLP265CA0401.GBRP265.PROD.OUTLOOK.COM
< x-beserver: CWXP265MB1910
< x-rum-validated: 1
< x-proxy-routingcorrectness: 1
< x-proxy-backendserverstatus: 200
< ms-cv: j81D4IB6E0dGIP4tuQABZQ.1.1
< x-feserver: CWLP265CA0401
< x-powered-by: ASP.NET
< x-feserver: LO2P265CA0472
< date: Sat, 16 Oct 2021 13:18:24 GMT
<
* Connection #0 to host xxxxx.webhook.office.com left intact

which I guess looks good. If I change the GUID-type part of the URL it fails, so the URL is correct. I can't check if anything arrived in the Teams channel until I go back to the office on Monday

can you show output of
curl -v https://xxxx.webhook.office.com/webhookb2/xxxxx

May be you will need to post the actual request prepared by netxms, in this case
curl -v -X POST https://xxxx.webhook.office.com/webhookb2/xxxxx
    -H "Content-Type: application/json"
    -d "{ "text":"NetXMS: [Normal] xxxxxx: Node up 28.Sep.2021 14:56:12\n\nNormal] xxxxxx: Node up" }"

Anyone know what that means? That normally means a redirect will happen. Is this normal behaviour?
Sorry, I've not used webhooks before....

Best regards,
Victor

2021.09.21 10:20:35.175 *I* [ncd.msteams        ] Microsoft Teams driver instantiated

I have the following in my Driver Configuration:

ThemeColor=FF6A00
UseMessageCards = false

[Channels]
Channel=https://xxxx.webhook.office.com/webhookb2/xxxxx

Attached is a picture of the error and of my notification action

I have updated documentation: https://www.netxms.org/documentation/adminguide/event-processing.html#drivers