Might be battery issue - generators take a lot of juice to start - even a corroded ground on generator or battery bank can be enough to create similar issue. Check the batteries, clean your battery terminals, check your grounds, and tighten all your connectors. Also consider cleaning the terminals part of the wiring harness which connects your remote start to generator.
When I try and start my generator I will often start the chassis engine first - that puts both the coach/chassis batteries in parallel and helps provide more power to start the generator.
