This error occurred when we install Oracle EBS R12.1 on oracle cloud.
CAUSES OF ISSUE
The http port number and instance public ip is blocked by the vcn network.
There is no symbolic link between libgdbm.so.2.0.0 libdb.so.2 library.
STEPS TO SOLVE THIS PRE CHECK ERROR
1.Configure Ingress Rule for EBS R12.1 Port Number And Public Ip
Networking->Virtual Cloud Networks->vcn->Subnet Details->select default security rule
Allow public ip to access cloud instance
2.Check Http Logfile
To Solve Can Not Open Shared Object File Error We Need To Create Symbolic Link
ln -s /usr/lib/libgdbm.so.2.0.0 /usr/lib/libdb.so.2
3.Bounce The Apache And Check The Status
4.Click retry button in installation
5.Post Install checks Successfully validated