​ To learn more, see the sources I considered: [[1] Error with Cal.com integration](https://discord.com/channels/1186424376300679209/1432628757067337778) [[2] Check Calendar Availability](https://docs.retellai.com/build/check-availability) [[3] Discord message from @jayzpio on 2025-03-06](https://discord.com/channels/1186424376300679209/1186462578310910112/1347215395622223903) ​

### Answer Based on community reports, several Cal.com integration issues have been identified: Common Issues: For team events specifically, users have reported "Event type not found" errors (404 status codes) even when the event type ID is correct and works in Postman. [(1) ]() The support team has indicated these issues should be resolved, but if you're experiencing problems with team events while individual events work fine, try rotating your API key. Another frequent error involves required phone number fields. If you see "attendeePhoneNumber error_required_field" errors, you need to disable the phone number requirement in your Cal.com settings. Setup Requirements: To properly configure Cal.com integration, you need: [(2) ]() 1. A Cal.com account 2. Your Event Type ID (found in the URL when viewing your event type) 3. Your Cal.com API Key (from Settings > Developer > API Keys) 4. Add these credentials to your Retell agent's check calendar availability function Prompt Engineering: Community members have found success by being explicit in prompts about date handling. The built-in integration can struggle with relative dates like "tomorrow" or "next week". [(3) ]() Consider including specific instructions about timezone conversion and date formatting in your agent prompts. If issues persist after checking these common causes, you may need to contact Retell support with your specific agent ID for investigation.

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

@AI Evy everything is done right the timezones are set right but still the agetns says that the time slot is not available and no near time slots

### Answer Based on community troubleshooting, this specific "no available slots" issue often stems from where you place your prompt instructions. [(1) ]() The Critical Fix: Place your availability check prompt inside the Cal.com function settings itself, not just on the conversation flow node. In the Cal.com function configuration, add a prompt like: "Check the availability for the user requested time and provide available slots, ALWAYS check for 2 hours span" Why This Matters: The payload your agent sends needs to check an appropriate time window. For a 30-minute appointment, it should query a 1-hour window. For a 90-minute appointment, it needs at least a 2-hour window. When the prompt is only on the node (not in the function) , the time span can revert to checking identical start and end times, which returns false negatives. Verification Steps: 1. Check your tool payload in the call logs - look for

start_time

and

end_time

in the function invocation 2. If they're identical or the span is too narrow for your appointment duration, that's your issue 3. Update the prompt in the Cal.com function settings (not just the node) 4. Test again and verify the payload now shows an appropriate time range You can also explicitly use the

{{current_time}}

or

{{current_time_[timezone]}}

dynamic variables in your prompts to ensure proper timezone handling. [(2) ]()

​ To learn more, see the sources I considered: [[1] Cal.com availability issues](https://discord.com/channels/1186424376300679209/1436100304558100540) [[2] Dynamic Variables](https://docs.retellai.com/build/dynamic-variables) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.