Error validating call.com tools

Support Help
1

Hello together,

everytime i try to connect retell ai with the api key from cal.com i get this error:

error validating call.com tools

i am trying to solve it but there is no chance for me…

Can somone help me please?

Thank you,

Marvin

2

Based on the sources, this “error validating cal.com tools” issue has been reported by multiple users and appears to have specific causes(1).

Common solutions to try:

  1. Rotate your Cal.com API key - Generate a new API key in your Cal.com dashboard under Settings > Developer > API Keys, then update it in Retell(2)(3).

  2. Verify your Event Type ID - Ensure the event type ID you’re using actually exists in Cal.com. You can find it in the URL when viewing your event type (e.g., https://app.cal.com/your-username/event-type/1427703 where 1427703 is the ID)(2)(4).

  3. Check for Round Robin events - There have been reported issues specifically with Round Robin team calendars. If you’re using a Round Robin event, try switching to a normal (single-user) event type temporarily to see if that resolves the validation error(1).

  4. Confirm API key hasn’t expired - Make sure your Cal.com API key is still valid and hasn’t been revoked(1).

Setup requirements:

When adding the Cal.com integration in Retell, you need to provide(2)(4):

  • Tool name (must be unique within that agent)
  • API Key from Cal.com
  • Event Type ID
  • Tool description
  • (Optional) timezone

If none of these solutions work, the issue may be related to a broader Cal.com integration problem that was reported in late October 2025, which has since been marked as fixed(1).

3

Couldnt solve i have the same error

4

Hello @Yelawolf

Can you share your agent id?