You need to resync tour wallet.
To make sure, the best way is:
1. Backup files (wallet.dat, masternodes.conf, polis.conf)
2. Download wallet again
3. Delete .poliscore folder.
4. Run wallet with -connect=polispay.org
5. Check out sync and make sure you are with the explorer.polispay.org
6. Stop wallet.
7. Replace files.
8. Run masternode again