Unable To Pair Watch - iOS Error Message

Hello,

After resetting my Apple Watch I am having trouble pairing my Apple Watch with my iPhone 6 Plus. During the pairing process (manually or otherwise) I receive this message "iPhone Out Of Date - Your iPhone is out of date. Before you can pair it with your Apple Watch, you'll have to update it to the newest version of iOS."

Funny thing is, I'm already running iOS 9.3.5 ...

I've tried restarting both my phone and watch, resetting my network settings, and read throughout the interwebs with no resolution. Yes Bluetooth is on, as is wifi. Please help.