My MVP requires an integration, how do I most effectively validate it?

I am building a product analytics tool called Tractific that was launched for beta 2 weeks ago. From our mailing list, we could only get a handful of people to sign up and integrate. Does this mean the idea is not valid or is it the integration process that is creating a bottleneck? A lot of people sign up and leave when they see the integration instructions. If it's the latter, how can I find beta testers for such a product?