Error Message to Reboot Router or Optimize Network

[pronick]

I'm using a hardwired ethernet connected Mac, OS 10.14, with a Steinberg UR22, and when joining a session with another musician who invited me, we both receive an error message that streaming audio may not be reaching others and to try to reboot the router or optimize my network. Is there a legitimate reason for this and what is the solution? Do I really need to reboot the router? How do I optimize my network?  

When joined into a session, my signal is greyed out.

Any help is appreciated.