Error after update latest firmware

One of my client getting error "configuration import fail" after he update cnMaestro to latest firmware and connection between AP and cnMaestro has been lost. There is no configuration has been changed.

Can you please send me the device serial no or MAC via private message

Okay im getting the serial no, i will email you with same title of this topic.

Thanks for your reply

What is the firmware running on your device?

We have some issue with 3.5-r1, so we would suggest you to downgrade with