Hello everyone
I have bought a Mikrotik CRS310 in my existing Ubiquiti network to use the 2.5Gbe interfaces to speed up my HomeLab.
Unfortunately I encountered some problems. I am not able to transfer the VLans correctly from Ubiquiti to Mikrotik. The server in VLan 20 is not pingable. The clients in VLan6 have no internet.
I have read various Youtube videos and also here in the forum and tried things out but I seem to have missed a point.
Here is the schematic and the config thanks already for Help.

The configuration you posted Is a partial one.
Particularly when there are connections issues it is needed a full configuration (edit it to mask sensitive data, serial, etc.) as the cause of the issue may be in an area that is (only seemingly) unrelated to the one(s) where you suspect being the problem and that you posted.

Dont use vlan1 for data on Mikrotik devices. Assuming vlan1 on the unifi.........is the trusted vlan.
How is vlan1 data getting to the mikrotik, assuming untagged as unifi doesnt normally tag the management vlan.
If so you could consder ETH1 being a hybrid port into the MT.

/interface bridge
add frame-types=all ingress-filtering=no name=bridge1 vlan-filtering=yes

add interface=bridge1 name=vlan11 vlan-id=11
add interface=bridge1 name=VLAN20 vlan-id=20
add interface=bridge1 name=VLAN6 vlan-id=6

/interface bridge port
add bridge=bridge1 interface=ether1 pvid=11
add bridge=bridge1 interface=ether2 ingress filtering=yes frame-types=admit-only-vlan-tagged
add bridge=bridge1 i interface=ether3 ingress filtering=yes frame-types=admit-priority-and-untagged pvid=20

/interface bridge vlan
add bridge=bridge1 tagged=bridge1,ether2 untagged=ether1 vlan-ids=11
add bridge=bridge1 tagged=ether1 untagged=ether3 vlan-ids=20
add bridge=bridge1 tagged=ether1,ether2 vlan-ids=6

/ip address
add address=192.168.4.X/24 interface=vlan11 network=192.168.4.0 { the mikrotik is a switch so should get an IP on the trusted vlan 11 )

The only address is the address of the switch, no others are needed.

Thank you very much for your contributions.
I have tested the configuration again. Created VLAN11 in Unfi and connected it to the port of the Microtik switch.

With US8 the devices work in VLAN 6

With the Mikrotik on E3, the Vlan 20 device cannot be reached with ping.

The Microtik management (Winbox) does not see the switch. The two Unfis switches US8 are also technically unreachable.

Thanks for further suggestions

Well if you can tag the management subnet traffic on the unifi to vlan11 then thats a different outcome right.
Also, only vlan needing definition is the vlan11 ( the management vlan )

/interface bridge
add frame-types=all ingress-filtering=no name=bridge1 vlan-filtering=yes

/interface vlan
add interface=bridge1 name=vlan11 vlan-id=11

/interface bridge port
add bridge=bridge1 interface=ether1 ingress-filtering=yes frame-types=admit-only-vlan-tagged comment="trunk from unifi"
add bridge=bridge1 interface=ether2 ingress filtering=yes frame-types=admit-only-vlan-tagged comment="trunk to downstream switch"
add bridge=bridge1 i interface=ether3 ingress filtering=yes frame-types=admit-priority-and-untagged pvid=20 comment="access port to server"

/interface bridge vlan
add bridge=bridge1 tagged=bridge1,ether1,ether2 vlan-ids=11
add bridge=bridge1 tagged=ether1,ether2 vlan-ids=6
add bridge=bridge1 tagged=ether1 untagged=ether3 vlan-ids=20

/ip address
add address=192.168.4.X/24 interface=vlan11 network=192.168.4.0 { the mikrotik is a switch so should get an IP on the trusted vlan 11 )

Thanks you very much Mesquite.

Client Devices and also the Server Vlan work now.

The UDM show the Unfi Switch after the Mikrotik offline but i think i can figure that out myself.

Big thanks

Thanks for reporting back, good news!