If you are using a Feig reader and have everything in ClearStream properly configured, yet seem to be unable to read any tags, you should check to see if the reader is in the correct operating mode.
Within the device configuration, you can select your reader, then go to the device tab. Feig readers will have an "Operating Mode" option that lets you select between buffered read mode and host mode. The default should be host mode, so you can switch to buffered read mode, apply, and restart the reader. Then switch back to host mode, apply, and restart the reader again.
What can happen (that this would fix) is that the reader may be in buffered read mode for a reason (could have been changed by another user, or changed before you received it), and ClearStream would not detect the change. So manually setting the operating mode back to host mode could fix this.