Why did the router stop seeing the provider's wire?

Question

Computer networks

Hello.
ASUS RT-N16 router, DD-WRT firmware (version v24-sp2 (08/12/10) mega).
Provider Flex .
The connection is made via L2TP. The provider provided the following information:

IP: 10.201.254.11
Маска: 255.255.255.0
Шлюз: 10.201.254.254
DNS1: 80.252.130.253
DNS2: 80.252.130.254

Сервер L2TP: 10.255.255.254
Логин и пасс L2TP

Everything worked fine for the last couple of years, but a couple of days ago the connection on the router flew off. In router status WAN IP: 0.0.0.0 (should be 10.201.254.11 ).
If you plug the provider's wire directly into the computer, everything works fine.
The provider does not have DHCP - the computer does not automatically pick up ip 10.201.254.11 when connected directly, you must manually specify them in the LAN connection settings. At the same time, in the router, if you select L2TP as the connection type, there are no fields for entering ip, mask and gateway (it turns out that I don’t specify them anywhere at all, I specify only the L2TP server, login and password), but ip is successfully picked up and the Internet works (more precisely, it was before).
I found this on the provider's forummanual for setting up a connection on dd-wrt, but it did not help either.
Tech support provider says that everything is ok. Where to dig?
UPD: ifconfig -a command output:

Answer 1

I sinned on a burnt WAN port, it turned out to be just dd-wrt glitches. After flashing the problem disappeared.

Answer 2

At the beginning, specify the static mode of operation on the DD, enter the IP addresses, save, reload, transfer the l2tp mode, supplement with a login and password.
Well, or try from another browser, perhaps something with the page markup and the browser simply does not show the fields, although they are =)
Well, the title of the question does not reflect the essence at all.