But since 4 days MN2 payed 4 times, MN1 payed once and the other two didn't pay at all.
Any suggestions how to see what is going wrong?
Issue `masternode list` from time to time to see if all your masternodes are present on the list.
After starting them they all appear in masternode-list, but after some time some of them disappear. Most of the time already the same day.