Foreign key constraint error when saving data to database

I am trying to save data into the Doctor table in the database. The table structure is shown below.

The error I get when saving

Microsoft.EntityFrameworkCore.DbUpdateException: An error occurred while updating the entries. See the inner exception for details.

Microsoft.Data.SqlClient.SqlException (0x80131904): The MERGE statement conflicted with the FOREIGN KEY constraint "FK_DoctorClinic_Clinic_DoctorId"

Table structure:

Doctor

Id 
Name

Clinic

Id 
ClinicName

DoctorClinic

DoctorId 
ClinicId

Code:

foreach (var clinicId in clinicIds)
{
     DoctorClinic doctorClinic = new DoctorClinic()
     {
           ClinicId = clinicId,
           DoctorId = doctor.Id
     };

     doctorClinicList.Add(doctorClinic);
}

doctor.doctorClinic = doctorClinicList;

var doc = await _docRepo.Create(doctor);

Note: I think the reason is that DoctorClinic requires a doctorID, and we don't have the ID as we have not saved it yet.