VPN L2TP on RB2011UiAS

Hi ,

On my RB2011UiAS I created a l2tp / IPSEC VPN.
It can not work despite having carefully followed the various tutorials on the web.
There is already an IPSEC PPTP VPN that works perfectly.
What could I do to solve the problem?

Help me please!

Start by posting your current configuration following the hint in my automatic signature below.