@warllo 

I think there is a difference between the SFP + DAC cables, some only support 10GB others have 1GB and 10GB, I use a unifi SFP+ DAC it supports both, I use it between an ER8411 10GB interface and an SG2428P which only has 1GB SFP

  @warllo It's either the cable or config. I have sg2210mp lagged to a sg3824x so going from SFP to SFP+ can work with DAC. Tripple check that the speed/duplex match (1000FD) on both ports. If that's correct it most likely your DAC. This is the ASIN (B09CDP6PG4) at Amazon for the cables I'm using.

@D-C 

Thanks for the response.

I've quadruple check the speed and duplex settings. I'm guessing its the DAC cable.

I'll try the one suggested.