Knipes, from Chelmsford, came through qualifying to earn a second visit to Royal Portrush, six years after becoming the youngest player to feature in the 148th Open at the same venue, in 2019, aged 18.
After a two-over-par first round of 73, Knipes followed that with a four-over-par second round of 75 on Friday to end his involvement before the weekend.
Knipes, who mainly plays on the HotelPlanner (Challenge) Tour, added: “[I’m] pretty disappointed. I feel like I’ve just not been sharp enough the last couple of days.
“I didn’t make a birdie [in second round]. Putter was very, very cold. If I actually putted well then maybe there would have been half a chance of making the cut. [I was] just a bit too off really.
“You don’t get many chances around here and I gave myself a good few looks, especially on the back nine and just couldn’t convert.
“You have a glimmer of hope and it strips right away from you so it’s pretty tough.”