I had this issue using Windows 7 and solved it this way:
Devices and Printers - WorkCentre 3215 Printer Properties - Sharing - Tick "Share This Printer"
I have the same problem with the Phizer 3020 printer. There are many similar complaints on various forums. In most cases, Xerox specialists say that you have a special case and either refer to the documentation for setting up Wi-Fi or recommend invite their specialist. On several, people write that they invited Xerox specialists and as a result they could not do anything - these stories basically end with replacing the printer with a printer from another vendor.
I have same issue.... hoping to see a solution. I found someone else he updated to fimware 655421 to give option to not allow USB to go into powersave mode, but I can't get the firmware to install, it says its not appliple to the 6515 workcentre.
Is it plugged into a surge protector? Ive had several machines not wake up both wifi and connected ethernet that were plugged into surge protectors. Plugged straight into the outlet and the issue was resolved.
Thanks Joe. I have tried to use the update tool with both versions 10.13 and 10.14 and with both versions the message is that the update tool is 'damaged'. So it will be good if Xerox can look into this. I have no windows machines. An important reason for choosing Xerox was that it is known as a 'blue-chip' manufacturer, whilst the printing otherwise is great, this software/firmware aspect is disappointing.
As for the older router, that unit was 6yrs old (and started to fail) so presumably this has something to do with the new router using an up to date version of the software protocols and the printer doesn't.
I can't help with 1 since it worked on the other router. But 2 can be worked around by using a Windows based product to run it. I've seen a few posts where peple could not get the update tool to function on their Mac, not sure as to why, it works on my 2 running 10.13 (Macbook) and 10.14 (Mac)
Thanks for your response Joe, wifi was already set as primary network
So we're left with 2 problems:
1. Wifi does not recover from sleep mode
2. Firmware update tool does not work
Login as admin and go to Device > Connectivity > Primary Network and set it to Wireless.
That's pretty much all you can do from the Xerox side, since the only thing that changed is the LAN, it isn't likely to be the printers fault, probably more that the printer was static IP before, or the LAN/Router was set to always give it the same IP address via DHCP, and the new one isn't.
Our 6515dni worked fine for 1+yr connected through wifi, and would come to live from sleep mode when a print job was submitted. With the new wifi system it now does not automatically come to live after more than a few minutes of sleep mode. The wifi system shows the printer is 'offline'.
When I switch the printer on through the touch panel, it works fine and I can copy/scan etc but it will still not print from my mac and the wifi system still shows the printer as 'offline'(!). When I power the printer off then on, it works OK and the printer shows 'online'. I have tried to give the printer a static IP address but no success. Moving the printer to an ethernet point (not where its needed) and connecting it with ethernet, the printer works fine and it comes back from sleep mode as it should.
I have tried to download the most recent firmware and the FW update tool, 'WC_6515_653181.dmg' but when I launch the update tool, I get a msg "Firmware Update Tool.... is damaged and can't be opened" so I am unable to update the firmware. I do not have a windows pc and so can only try the mac version.