Tokyo to Matsumoto

Dear,

We want to travel from Tokyo to Matsumoto (using JRP) on Thursday the 13th of July.
When I input this in Hyperdia.com (9:19 AM we are flexible though) it gives me route not found... (is this because there are no trains in the morning?).
Through google I found that there is a train in late afternoon (6PM) but the Hyperdia also gives me warning that it may contain some routes not valid for JRP. Best option with Shinkansen to Nagano and then JR Shinonoi line.
Could you help me please what best route would be using the JRP only?

Kr

Dieter