I have never had to Manually specify Mechanical APDL solver memory settings on a well equipped computer. The only time I did was to help a student on an old computer with only 2 GB of RAM, while ANSYS specifies the minimum RAM is 4 GB. The default setting for Database is 2 GB of RAM which caused the same error you saw on a computer that only has 2 GB of RAM. To help that student, I recommended 1 GB of memory for the Database and that allowed that very small model to solve.
Try these settings.