Slack Thread Message Not Working via Pabbly API

Dear Pabbly Support Team,

We are integrating our custom Slack app QS-Buddy with Pabbly Connect using the Slack Web API.

The API request to:

https://slack.com/api/chat.postMessage

is working successfully for normal channel messages and returns:

ok = true

However, when we pass the parent message timestamp using the parameter:

thread_ts

the message is still posted as a new top-level message instead of appearing as a reply in the existing Slack thread.

We have already verified the following:

• 
  1. Correct Slack Channel ID is being passed.
• 2. Correct parent message ts is being used as thread_ts.
• 3. The timestamp is stored as plain text in Google Sheets.
• 4. QS-Buddy has the required Slack permissions and is already added to the private channel.
• 5. API response is successful with ok = true.
• 6. The response does not show message.thread_ts, which suggests the thread_ts value may not be reaching Slack correctly.
• 7. We also see a missing_charset warning, although the API call itself succeeds.

We have tried both:

• 1. Standard API request with parameters
• 2. Custom Request with JSON payload

but the Slack thread reply is still not working.

Please advise the correct Pabbly configuration to send a Slack chat.postMessage request with thread_ts so the message is posted inside the existing thread.

I will attach screenshots of the request, API response, Slack message link, and task history for reference.

Thanks & Regards,
Ojasv
QuickShip Global Express