Communication between two USRP : mismatched spectra between transmission and reception
A few (hopefully useful) comments and ideas:


The HackRF One is not a USRP.
If you're receiving with an NI 2921 USRP, you should be using UHD to interface with it, not osmocom.
Use a standalone spectrum analyzer, first to double-check that nobody else is transmiting at that frequency, and then to study your transmitted signal.
Transmit a single sine wave and verify that both the spectrum analyzer and the USRP can see it. Verify that you're transmitting it with enough power.
If that works, try with two sine waves separated by a few kHz.
It is normal that the received signals are at a slightly wrong frequency. Each device has its own idea of what 1 Hz is; this is why receivers need to run a carrier synchronization algorithm.
Your devices may not support a sampling frequency of exactly 200 kHz and may be using the closest available frequency. Check any warnings on the console. This may result in impaired performance.
In general, pay attention to any output on the console: you may be overrunning or underrunning your flowgraphs, or something else may be wrong.