The basic trouble shoot For OAM and EBS Accessgate
Troubleshooting Oracle Access Manager and Oracle E-Business Suite AccessGate (Doc ID 1077460.1)
Integrating Oracle E-Business Suite Release 12 with Oracle Access Manager 11gR2 (11.1.2) using Oracle E-Business Suite AccessGate (Doc ID 1484024.1)
Troubleshooting Oracle Access Manager and Oracle E-Business Suite AccessGate (Doc ID 1077460.1)
Integrating Oracle E-Business Suite Release 12 with Oracle Access Manager 11gR2 (11.1.2) using Oracle E-Business Suite AccessGate (Doc ID 1484024.1)