Output Journal Error

Dear All,

I don't know why sometimes when i open output journal in NAV 2016 some routing line does not exist error popes up and my users are unable to enter their output in to the journal to solve this either i've create a new output journal batch or i've go to item table through dev environment and run item journal line table and delete the line or entry with the routing no. shown the error message. until now i was handling the issue this way but lately it is happening frequently and creating a big set back in our day to day activity. What could be the cause and what should i do the solve the issue permanently. Thank you. below i've attached the screen shot of the error message