How to configure netgear windr 4500 router for L2TP VPN connection?

Question

Network administration

Good afternoon.
Here is what is available:
mac mini server
router netgear windr 4500
white IP address
On mac mini, VPN server L2TP is configured, port 1701 is forwarded in the router
Everything works from the internal local network and connects through operating systems: MAC OS, Windows, android and IOS
But nothing I can’t connect from an external network to L2TP VPN from Windows and Android operating systems, while Apple devices are connected.
Tell me how to properly configure the router?
I read on the net that there are such problems and they are solved by buying an Apple router, but my router suits me quite well.