There are some specific procedures to keep in mind for submitting specifically Medicare claims.
What is the procedure in View/Edit claims to resubmit a claim to Medicare?
When re-submitting a claim in View/Edit claim screen, instead of selecting "7-Corrected Claim" in Box 22, leave the number as 1 with no ICN in the box. For medicare, re-submissions must be originals with no claim number (ICN) entered.