Kernel debug taken during the issue (fw ctl debug -m fw + drop) shows the following drop of IKE connection: fw_log_drop: Packet proto=17 X.X.X.X:500 -> Y.Y.Y.Y:500 dropped by fwpslglue_chain Reason: PSL Drop: ASPII_MT;
Kernel debug taken during the issue (fw ctl debug -m fw + drop) shows the following drop of RDP connection: fw_log_drop: Packet proto=17 X.X.X.X:259 -> Y.Y.Y.Y:259 dropped by fwpslglue_chain Reason: PSL Drop: ASPII_MT;
IPSec VPN Link Selection in VPN Gateway object is set to 'Use probing. Link redundancy mode'.
Cause
The IKE (UDP port 500) connection or RDP (UDP port 259) connection is dropped by the Application Control Blade.