All my masternodes seem to be getting
"ERROR: ProcessBlock() : CheckBlock FAILED"
and
"ERROR: CheckBlock() : Couldn't find masternode payment or payee"
since 14th february. Some of them have received payments even with those messages.

Finally fixed my masternode issues with -reindex after receiving no payments for more than a week.
drk.mn says there is 1711 unique IPs out of 1900+. Is it possible to run multiple masternodes on the same ip?

My 5 masternodes have been active for more than 3 days according to drk.mn but not a single one have received payments.
What's going on?
Running 0.11.0.13.