AC1200 EX6150v2 not detecting 5Ghz from modem

Hello,

I have an old AC1200 EX6150v2 extender that has the latest firmware.  My issue is it is not detecting the 5Ghz connection from my modem. The modem is a Verizon G3100 modem/router and is a triband (2.4, 5.1 and 5.2)

Since this extender only detects dual band and router is sending tri band, would this be the issue?  Or is the extender to old to detect all the bands a new more modern one is needed?  Would I need to deactivate one of the bands on the modem to get this to work?

thanks for any help or suggestions.