This reminds me of my old tech support job when dialup was the way you got online from home. I was befuddled by a user that could not connect, and nothing I tried over the phone worked. So I decided a house call was in order and drove the 50 miles to the customers house on my own time just because I needed the challenge.
Upon arrival, I connected my laptop to their phone line and attempted to connect. Whilst the loud negotiation tones rang from my speakers, I noticed the sound cut out once every second. Having grown up on a farm, this sounded suspiciously familiar. I picked up on the phone line and heard an even more familiar ticking sound that told me exactly what the problem was. I asked the customer if they had recently installed an electric fence, which they confirmed. After unplugging said fence, Internet connectivity was promptly achieved.