Increase the Java maximum heap memory available to WorldServer, after first checking to see that more memory is available on the application server machine.
In Windows, this can be done from a command window, assuming the user has sufficient privileges.
Starting from version 10.4.5 and later versions, follow the instructions in this article:
WorldServer - How to change the Java Heap MemoryIn earlier WorldServer versions (up to 10.4.4.), follow the steps described in this article:
Tuning performance of SDL WorldServer 10.4.4. and earlier version by changing the Java max Heap settings