Calendly Messenger Sheet fails with HTTP 400 on iOS SDK 19.8.2 | Community
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Question

Calendly Messenger Sheet fails with HTTP 400 on iOS SDK 19.8.2

  • September 24, 2026
  • 0 replies
  • 4 views

Hi,

We’re experiencing an issue with the Calendly integration inside the Intercom Messenger on iOS.

The Calendly app is installed and configured in our Intercom workspace. The booking flow opens correctly and allows the user to select a date/time and enter their details, but submitting the Calendly form fails.

Xcode shows the following error:

[Intercom] ERROR - Tried to submit messenger sheet but there was a network error - HTTP Error: 400 bad request

The same Intercom message and Calendly flow works on Android and proceeds past this step.

Environment:

  • Intercom iOS SDK: 19.8.2
  • Installed via Swift Package Manager (intercom-ios-sp)
  • Flutter app using intercom_flutter
  • Calendly native Intercom integration

We also updated the Intercom Flutter plugin/native SDK, but the issue persists.

Has anyone encountered this with Calendly Messenger Sheets on iOS, or is this a known issue with the current iOS SDK?