The high-E string (at the bottom of my guitar) recently began buzzing on my Ovation 1867 acoustic/electric guitar. Does anyone happen to know what might be causing this?

I have a friend who is a musician and he told me to adjust the tension rod in the neck using an allen wrench. Think this will work? Does anyone happen to know what allen wrench I'll need for this specific guitar?

Also... I have old strings on my guitar... could that be causing the problem?

Any insight would be much appreciated.
Do not adjust the truss rod.
Have a professional do that, or you're gonna break your neck.