Never really set up tunnel between CP and Aruba personally, but can ask one of my colleagues who is really good with Aruba to see if there are any known settings/issues to be aware off. Did the tunnel ever work right or you had problem since the beginning? As @PhoneBoy said, debugging this is a really good idea on CP side.
This is what I usually do, super easy process...on CP fw, rune below commands from expert mode:
vpn debug trunc
vpn degug ikeon
generate some traffic
vpn debug ikeoff
Get vpnd.elg file, as well as ike,elg from %FWDIR/log
Use ikeview utility (free to download off google) to examine ike.elg file and look for the entry for Aruba public IP in there and see whats happening. Also, vpnd.elg can give some insights as well.