My Verifone VX 520 is stuck on the CommServer screen. How do I fix it? Rene Leveque March 27, 2018 15:57 Updated Follow Simply press F3 to get to the main sale screen you are used to seeing. If you need help, call us at 408-295-8360. Related articles When I try to run a transaction on my Verifone VX 520, I get an error that says "No Line/No Host Response/ No Dial Tone." How do I fix this? My settlement failed on my Verifone VX 520. What happened? Comments 0 comments Please sign in to leave a comment.