Portchannel not coming up between arista switches and cisco ASA

[cure]

Hello,

I'm trying to setup a portchannel between Arista DCS-7280SR2 and Cisco ASA, but it's not working. I can see the physical interfaces up but not the Po. Is it something that I missed to add? 

                                 ASA

                eth0/1   /             \ eth0/2  

                        /                     \

            et28 /                            \ et28

       Arista SW1  ===mlag==== Arista SW2

ASA#

interface port-channel 1
security-level 0
nameif outside
security-level 0
ip address x.x.x.x/x
no shutdown

!

interface et 1/1
channel-group 1 mode active

no shut

interface et 1/2
channel-group 1 mode active

no shut

Arista SW1 and SW2#

interface Port-Channel10
switchport access vlan 537
mlag 10
spanning-tree portfast

no shut

!

interface Ethernet28
speed forced 1000full
channel-group 10 mode active

no shut

[MHM Cisco World]

https://www.fir3net.com/Firewalls/Cisco/configuring-etherchannel-on-an-asa-firewall.html

Try this way

[cure]

Actually I tried this way as below, the only thing I haven’t done was to put the speed settings on the physical ports.

interface Port-channel1.537
  vlan 537
  nameif Outside
  security-level 0
  ip address xxxx/x

I’ll try to add the speed on the int 1/1 and 2.
thanks

[cure]

I tried again the solution you shared Friday and I also added the speed 1000 and duplex full but didn't work.

ASA#

# sh run int po1.537
!
interface Port-channel1.537
vlan 537
nameif outside
security-level 0
ip address XXXX/X

# sh run int e1/1 (same for int  1/2 )
!
interface Ethernet1/1
no switchport
channel-group 1 mode active
no nameif
no security-level
no ip address

# show interface port-channel 1.537
Interface Port-channel1.537 "outside", is down, line protocol is down
Hardware is EtherSVI, BW 20000 Mbps, DLY 1000 usec
VLAN identifier 537
Full-Duplex, 1000 Mbps

# sh int e1/1
Interface Ethernet1/1 "", is up, line protocol is up
Hardware is EtherSVI, BW 1000 Mbps, DLY 10 usec
(fullDuplex), (1gbps)
Active member of Port-channel1

ON the ARISTA switches 

)#sh run int e28
interface Ethernet28
speed forced 1000full
channel-group 1055 mode active
#sh run int po1055
interface Port-Channel1055
switchport access vlan 537
mlag 1055
spanning-tree portfast

On the ARISTA I also configured the Po as trunk, since the ASA was already tagging the traffic with vlan 537, but still didn't work

#sh run int po1055
interface Port-Channel1055
switchport trunk allowed vlan 537
switchport mode trunk
mlag 1055
spanning-tree portfast

Please let me know if is anything else that I should try it.

[MHM Cisco World]

I check your config is OK, 
except one point, 
the PO is L3 and it member is L2 convert to L3 with no switchport 
can you add no switchport under PO and check again ?