As Pmalek pointed out, there have been similar topic on this issue sometime back. When the Core has ran out of virtual memory I guess this issue pops up. Core uses above the normal memory to access and run the application. Just edit the .config file of Bitcoin Core and add
-dbcache= a value lesser than allocated RAM If this doesn't solve your problem try to edit the config file and type
-maxmempool=value less than 300These should have lesser ram usage than your current scenario. There are other ways to reduce the RAM usage. Check this out :
reduce-memory