LinkedIn cold outreach popped for two weeks, then died for two months

Hi guys,

First two weeks of LinkedIn cold outreach went really well: about 21% positive reply rate over 30 sends. Then it fell off a cliff. Same target market, same template, I changed nothing (all new cold contacts cold and no warm contacts at all).

Since then I've sent way less, about 5 per week vs. 15 per week back then. I still get the occasional reply, but it's almost always polite variations of "thanks, not interested." This is been going on for two months now.

I'd love input from people who've seen this before to understand what is going on and how to move the needle.