Whenever you encounter the "Failed to Create Reservations - Invalid CompanyId" error when attempting to create a Reservation Group in the Reservations tab in Event Temple follow these steps:
Go to MEWS and add the Reservations
In Event Temple go to the Reservations Tab
Click the Link button
Enter the dates of the Reservations
Click Search
Find the name of the Reservations in the list
Click Link next to the name of the Reservations
Please Note:
If a Room Block already exists on the Booking you will not be able to Link any Reservations. You will need to remove the Room Block to have the option to Link a Reservation.