Nethserver IPsec and Fritzbox 5490

NethServer Version: NethServer release 7.7.1908 (final)
Hey Nethserverians !
I need help regarding IPSEC Tunnels. I’ve been working from many weeks to implement IPsec between [Nethserver 7.7.1908] [FritzBox 5490]. I’ve read all these forums but nothing seems to be working.
I am using Nethserver as Gateway.

I am not able to connect from FritzBox network using IPsec tunnel to Nethserver.
Please guide me what I am missing.

You may use this thread as starting point:

Please share your config files/screenshots to check what might be wrong.