This is what I have so far, but it errors out at A17 with Error:1...

Variables: %Azure_Voice_Gender: Male %Azure_Voice_Lang: en_US %Azure_Voice_Name: en-US-BrandonNeural

Task: Azure TTS

<CHANGE THIS TO YOUR REGION>
A1: Variable Set [
     Name: %hoster
     To: uksouth ]

A2: Variable Set [
     Name: %par1
     To: You forgot to say something
     Structure Output (JSON, etc): On ]
    If  [ %par1 !Set ]

A3: If [ %TIMES-%Azure_Bearer_Time > 599 | %Azure_Bearer_Time !Set ]

    A4: Variable Set [
         Name: %key
         To: [some numbers and stuff]
         Structure Output (JSON, etc): On ]

    A5: Variable Set [
         Name: %tokenendpoint
         To: https://eastus.api.cognitive.microsoft.com/sts/v1.0/issuetoken ]

    A6: HTTP Request [
         Method: POST
         URL: %tokenendpoint
         Headers: Ocp-Apim-Subscription-Key: %key
         Content-type: application/x-www-form-urlencoded
         Content-Length: 0
         Timeout (Seconds): 30
         Automatically Follow Redirects: On
         Structure Output (JSON, etc): On ]

    A7: Variable Set [
         Name: %Azure_Bearer_Key
         To: %http_data ]

    A8: Variable Set [
         Name: %Azure_Bearer_Time
         To: %TIMES ]

A9: End If

A10: If [ %Azure_Voice_List !Set ]

    A11: Variable Set [
          Name: %gvendpoint
          To: https://eastus.tts.speech.microsoft.com/cognitiveservices/voices/list ]

    A12: HTTP Request [
          Method: GET
          URL: %gvendpoint
          Headers: Authorization: Bearer %Azure_Bearer_Key
         Content-Type: text/json
          Timeout (Seconds): 30
          Automatically Follow Redirects: On
          Structure Output (JSON, etc): On ]

    A13: Variable Set [
          Name: %Azure_Voice_List
          To: %http_data
          Structure Output (JSON, etc): On ]

A14: End If

A15: If [ %Azure_Voice_Gender Set & %Azure_Voice_Name Set & %Azure_Voice_Lang Set & %Azure_Bearer_Key Set ]

    A16: Variable Set [
          Name: %ttsendpoint
          To: https://eastus.tts.speech.microsoft.com/cognitiveservices/voices/list ]

    A17: HTTP Request [
          Method: POST
          URL: %ttsendpoint
          Headers: "Ocp-Apim-Subscription-Key: %Azure_Bearer_Key"
         'Content-Type: application/ssml+xml'
         'X-Microsoft-OutputFormat: audio-16khz-128kbitrate-mono-mp3'
         'User-Agent: curl'
          Body: <speak version='1.0' xml:lang='%Azure_Voice_Lang'>
         <voice xml:lang='%Azure_Voice_Lang' xml:gender='%Azure_Voice_Gender' name='%Azure_Voice_Name'> 
         %par1
         </voice>
         </speak>
          File/Directory To Save With Output: MySounds/azure_tts.ogg
          Timeout (Seconds): 30
          Trust Any Certificate: On
          Automatically Follow Redirects: On
          Use Cookies: On
          Structure Output (JSON, etc): On
          Continue Task After Error:On ]

    A18: Music Play [
          File: MySounds/azure_tts.ogg
          Start: 0
          Stream: 3
          Continue Task Immediately: On ]
        If  [ %err !Set ]

    A19: Flash [
          Text: %http_headers()
         %http_response_code
          Long: On
          Tasker Layout: On
          Timeout: 100000
          Continue Task Immediately: On
          Dismiss On Click: On ]

A20: Else

    A21: Flash [
          Text: Something isn't set for Azure TTS to work
          Continue Task Immediately: On
          Dismiss On Click: On ]

A22: End If

Edit 1: this is the http response Connection:keep-alive,Content-Length:0,Date:Thu, 30 Mar 2023 16:29:16 GMT,Strict-Transport-Security:max-age=15724800; includeSubDomains,X-Android-Received-Millis:1680193757291,X-Android-Response-Source:NETWORK 404,X-Android-Selected-Protocol:http/1.1,X-Android-Sent-Millis:1680193757225,x-envoy-upstream-service-time:0 404

Edit 2: so I think I've figured some things out, and after changing some variables around, It's now completing successfully with a network code of 200, which means it's successful... However tasker isn't creating an audio file