I can't access remote Mikrotik via web. Who can tell?

Question

Computer networks

Thus it responds and is available on a telnet. On the web comes through once. Those. sometimes it comes sometimes it doesn't. No one except me configures anything . When it doesn't come in, it says this: You have connected to a router. Administrative access only. If this device is not in your possession, please contact your local network administrator. The remote microt sits on a private, dynamic address, receives via PPPOE. Therefore, the L2TP tunnel has been forwarded.
New information: Initially on the tunnel MTU 1450. When you change to 1400 everything starts working. But why when 1450 works through time. Why does it depend?

Answer 1

Changed MTU from 1450 to 1400 and it worked

Answer 2

Therefore, the L2TP tunnel has been forwarded.

What is the tunnel for, to administer from the outside? Does it let you into the web admin panel without it?

Answer 3

Have you tried logging in from different browsers?

Answer 4

ip service export compact
Look at the output - maybe you have a restriction on IP.
Also check the firewall on port 80