This coin is so broken, dev couldn't handle right the masternode, now all miners get rejected shares from all pools
i mined XDNA on bsod yesterday and it was good and profitable. I dont know about masternode problem but i can see that 155 MN are "ENABLED" and working fine. Maybe the problem is yours.
And also you can check that there is a good MN guide here
https://github.com/XDNA-Core/XDNA-InstallMN