The super hub 3 will not allow a hp 2600 or 2700 series printer to join the network. We are joining the 2.4 ghz network as we know that this is the only band that the prnters are compatible with. After many sessions on the phone with HP we have narrowed it down to the superhub as not being ccompatible. Are there any settings to change to connect them?
Have you tried splitting the 2.4GHz and 5GHz wireless by giving them two separate SSID names?
Also, when you are doing the initial printer setup/config, I have found in the past that downloading the full HP driver/utility software to a laptop then doing the first setup config of the printer via a USB connection and entering the wireless info that way gave the best chance of making a connection.