Out of nowhere I tried to use my agent and I can’t get it to book appointments anymore, I did nothing new to the functions working before, now it sends the payload wrong has the phone number as the email, Cal event is set up right and Agent too, could this be a retell bug? I need Urgent help! Also It says the correct times 10 AM to - 8 PM working hours but when I ask it what time is free in a day ( clear calendar) it says from 13 pm - 8 pm, no idea why. Romanian language and time for context. Agent ID: agent_5a79c6c498502cd5fd8b42bdc5
A call that had the same issue if it helps: call_bca2be60f4bb353103033d9f55b
Hey @lukasandrei2525 Thanks for the information , checking it with the team.
Thank You
Thank you im now trying to make a workaround using Make but no luck i keep bumping into errors rather than the simple Retell-Cal integration that was working wonders before hopefully u can help.
Hey @lukasandrei2525 what i can see is
Issue 1: attendeePhoneNumber error (phone sent as email)
The Cal.com error clearly states: "BAD_REQUEST","responses - {attendeePhoneNumber}error_required_field". This means your Cal.com event type has a required attendeePhoneNumber field configured, but the agent is sending the phone number in the email field instead. This is a Cal.com event type configuration issue — check your event type’s booking fields in Cal.com and ensure the field names match what the agent sends.
Issue 2: Availability showing 13:00–20:00 instead of 10:00–20:00
The tool result in your screenshot shows "availability_range":["From 10:00 AM to 5:00 PM"] — Cal.com is only returning up to 5 PM, not 8 PM. This is coming directly from Cal.com’s API response, meaning your Cal.com working hours or event type availability may not actually be saved as 10 AM–8 PM on their end. Double-check your Cal.com schedule settings.
Based on the logs, the payload and availability data are being passed through as-is from Cal.com — this points to a Cal.com configuration mismatch rather than a Retell platform bug.
Thank You
Hey @lukasandrei2525 Yes, based on your screenshot this is not a Retell prompt or setup issue — it’s a Cal.com configuration issue:
Phone number as “Required” field: Retell’s built-in book_appointment_cal tool only sends name, email, time, and timezone to Cal.com. It does not send a phone number field. Since your Cal.com event has Phone number = Required, Cal.com rejects the booking with attendeePhoneNumber error_required_field.
Fix: In Cal.com → Event Type → Booking Questions, change Phone number from “Required” to “Optional” (or disable it entirely). That alone should fix the booking failures.
Hey @lukasandrei2525 I checked it with the team and the booking tool sent email: null and no phone field, so Cal.com replied 400 – Attendee must have at least one contact method (email or phone number). The booking tool’s parameters (name / email / phone) are derived from your Cal.com event type’s Booking Questions. Retell doesn’t add a phone parameter unless that question exists on the event type.
On the Cal.com event type, make sure the Email booking question is enabled and required, then update the agent prompt to explicitly ask the caller for their email before booking. Right now the prompt says “Do NOT ask for an email address”, which is why null was sent.
For the “13 PM – 8 PM” issue: check_availability_cal already returns times in the timezone you passed (Europe/Bucharest), not UTC. Your prompt’s “READING RESULTS RULE” tells the model to add +3h to the returned range, which turns a real 10:00–20:00 window into 13:00–20:00. Please revise that logic.
Thank You