An out-of-the box A-Series Access Point not checking-in and flashing yellow would indicate that the AP has access to the internet and CloudTrax but isn't paired to a network.
The most likely issue is a typo was made when adding the MAC address to CloudTrax. Double check the MAC address and adjust accordingly.
If you are sure the MAC address is correct and the unit remains flashing yellow please open a ticket with support from: https://help.cloudtrax.com/hc/en-us/requests/new .
If your AP has checked in previously but is now flashing yellow, this would indicate that you simply need to re-pair the unit using the prompt at the top of CloudTrax.