Hello NotMe9,   It could be from it being cabled wrong or configured differently on the other end. Has it ever worked? What is the configuration on the S4048T for the port channel ?
I'm replacing an HP 2920-48G with LAG configured with a S3148p and I'm trying to LAG/LACP ports 1 and 2 of the S3148p to connect to a Dell S4048T-ON. On an HP switch, which I'm familiar working with, creating a LAG is just a couple of mouse clicks. On the Dell S3148p, which I'm not familiar with, it's interesting. The Internet searches I've performed have been no help. I get some variation of these errors: % Error: Gi 1/1 Port is part of a LAG.% Error: Gi 1/2 Port is part of a LAG.% Error: Port is not in Layer-2 mode Gi 1/1.% Error: Port is not in Layer-2 mode Gi 1/2.CMD-(CLI):[Error: Port is not in default mode Gi 1/1]by default from consoleCMD-(CLI):[Error: Gi 1/1 Port is part of a non-default VLAN.]by default from consoleCMD-(CLI):[Error: Port is not in default mode Gi 1/1]by default from consoleCMD-(CLI):[Error: Port is not in Layer-2 mode Gi 1/2.]by default from console Here is one of the many variations of commands I've tried: {  s3148p#confs3148p(conf)#interface range gigabitethernet 1/1-1/2s3148p(conf-if-range-gi-1/1-1/2)#portmode hybrids3148p(conf-if-range-gi-1/1-1/2)#switchports3148p(conf-if-range-gi-1/1-1/2)#port-channel-protocol lacp% Error: Port is not in default mode Gi 1/1% Error: Port is not in default mode Gi 1/2s3148p(conf-if-range-gi-1/1-1/2)#exits3148p(conf)#interface gigabitethernet 1/1s3148p(conf-if-gi-1/1)#port-channel-protocol lacp% Error: Port is not in default mode Gi 1/1 } Is there a s31xx specific guide other than the command guide which was no help that explains how to configure LAG/LACP on s31xxs switches? Thank you!
Configuring LACP on an S3148P