I have three RAPs that I use when I travel, a RAP-155, RAP-109 and RAP3-WNP. All three are running the same IAP verson 6.4.2.6-4.1.3.0 and have the exact same configuration on them. I use these for connctivity to my office via an IAP-VPN tunnel to an Aruba 3400 runing AOS 6.3.1.22. When I power them on they all come up and the tunnel is established back to the office as expected. I'm able to ping my corporate network and access internal services.
The issue is with the RAP3. After it comes up, the VPN connects for about 30 seconds and then goes down. Loging in to the IAP console shows the VPN as down. Disabling and re-enabling the VPN does not bring it back up. Rebooting the RAP3 does bring the tunnel up but it goes down again after 30 seconds. This does not happen on the RAP-155 or RAP-109.