you installed serial binding right?
I have a Linear HUSBZB-1 see the first post in this thread for a picture of it. It does zigbee & zwave I use both. It cost me about $30 usd
here is another link to a thread I started while trying to get mine working. and it includes many things to check and how
Here is a link where Lorenzo is trying to get his working - lots of great debugging techniques
Here is link to the zigbee binding thread (over 2000 posts) basically the encyclepedia of zigbee development
These things won’t help if the binding does not support the dongle . This dongle, while it’s an Ember inside, uses custom firmware.
As suggested above, the HUSBSB-1 is a good option in the US as it also contains ZWave.
Otherwise, the Telegesis ETRX357 dongle is well supported, but does not have a good upgrade path (although that said, the HUSBZB-1 is also limited in this respect because it doesn’t contain a bootloader so also can’t be updated).
In Europe there is another dongle made by Bitron and sold by Qivicon which includes the EM357 - it will work well under Linux, but as it has non-standard device codes, it’s not recognised in Windows or Mac.
The other option is the TI2531 based dongles - these are ok, but have issues at the moment with support. I’m currently rewriting the driver for this so hopefully the newer firmware will be supported in future.