Establishing Mesh Network connectivity

Hi All!
I am attempting to create a ZigBee mesh network between an Xbee 3 (acting as a coordinator) and several Xbee 2 pros (acting as routers). I have managed to establish mesh connectivity between the Xbee 3 and four Xbee 2s, and am now trying to configure eight more Xbee 2s to add to the network. I am using Xbee 2s which have been previously used for another project, so I am resetting them completely, reflashing the firmware, and then loading the working configuration profile from the Xbee 2s which are already in the network. Despite all of that, the Xbee 3 cannot find the new Xbee 2s, and I have not been able to add any to my network.
I am using the Grove Dev boards and XCTU. My configuration files can be found here.
Are there additional steps I need to do in setup to add routers to my network? I have given all the Xbees the same PAN ID, and for previous Xbees it seemed like just a matter of connecting the coordinator the XCTU’s network working mode and seeing connected Xbees.
Thanks so much!

Try turning on Joining by setting NJ to FF on both the XBee 3 Coordinator and on the S2C Routers.

Wow, thank you that is working like a charm so far. Should NJ be set back to FE once the connection is established?

Yes you can set the NJ to any desired value after the connection has occurred.