Hello everyone

I've been trying to resolve this problem the whole last week and today I just don't know what else I can try. I'm hoping someone can help. I have a S5296F (switch1) - firmware: 10.5.3.6, which I am trying to connect with a N1500 (switch2) - firmware 6.1.7.21, using DELL 10G transceivers with OM4 cables. I have established that there is link between the locations using the Fiberlert pen on both ends. The pen will beep, when there is light. So the physical link is there but the TenGig ports I'm using do not come up. They are constantly down. I'm using port channels.

• The port channel config on sw1 is: 

interface port-channel80
no shutdown
switchport mode trunk
switchport access vlan 1
switchport trunk allowed vlan (various VLANs)
vlt-port-channel 80

• The running-config for TenGig interface on sw1 is:

interface ethernet1/1/80:1 (speed manually set to 10G)
no shutdown
channel-group 80 mode active
no switchport
mtu 9216
flowcontrol receive on

---------------------------------------------

• The port channel config on sw2 is: 

ip dhcp snooping trust
ip arp inspection trust
ip arp inspection limit none
switchport mode trunk

• The running-config for TenGig interface on sw2 is:

channel-group 1 mode active
ip dhcp snooping trust
ip arp inspection trust
ip arp inspection limit none
spanning-tree portfast
switchport mode trunk

Both transceivers are DELL SFP+ 10GBASE-SR

What I have tried so far:

-  checked that both switches can see the transceivers and they both come up as DELL EMC qualified: YES

- tried different transceivers

- checked logs but all I can see is messages about the transceivers being removed and inserted back in.

Is there anything obvious I'm doing wrong? Please let me know. What else could I try?

Thank you in advance.