This can happen, depending on the environment you're testing in. When you say "closed environment" what do you mean? If this is a lab scenario, I would strongly recommend following the directions in this thread.
I would also suggest upgrading to R15.1.1, the latest software just released, which includes many improvements for 450m (please read the release notes), and can be found here.
If you're still having trouble, we'll want to capture some diagnostics from the radio.
If it was working, then exhibited symptoms such as these, I expect that something has failed with the unit. If the unit is still under warranty, I would suggest that you open a support ticket to dig into this further.
Please open a support request as Matt recommends. If you have not purchased an advance replacement or extended warranty, you will need to ship the unit to Cambium for repair and return.
We are having this issue on one of our Medusa sectors. Has anyone figured out what causes this, or a fix rather than hiring a climbing crew and replacing the unit?
We are having the same issue on one of our units. Cambium wanted to move to RMA immediately, no suggestions of updating firmware. Have there been any incidents where the upgrade actually fixed this? I am probably going to try loading 21.1.0.1 on the unit. it is out of warranty anyways, so worth a shot before RMAing
In R21.1.0.1 the tracking number and description for fixing at least one cause of the “Transmit Disabled (internal reason code 02)” error is described as “450m CPY-18021 TXFB tracking outside of tolerance after upgrading to System Release 21.1.”
AGAIN, if updating to R21.1.0.1 doesn’ resolve this issue for you, then you’ll need to open a ticket and most likely RMA.