Why does access to mikrotik disappear when setting up a VLAN?

Question

Mikrotik

Hey! I configure VLAN on the CSS326-24G-2s + device according to this article (VLAN Example #1)
When I plug the trunk port into the return port of the router, the vlans rise as they should.
But! The control of the device itself disappears, the web interface is not available, winbox does not find it. I throw it back to the usual port, find it and go to the web interface.
Here are the settings of the System tab:

Answer 1

line allow from vlan
you need to specify management there, right?
judging by the settings, he is trying to get himself an ip by DHTsP (Address Acquisition) but it is not indicated from which vlan.

Answer 2

What is your Management VLAN? Do you give it to the router in the trunk? Where are the configs of what you stuck?

Answer 3

Must be managed with VLAN40. On a router leaves in a trunk.
Only it is not clear where to indicate that he should receive ip from VLAN 40. I
tried to search for both VLANs.