Before you try to fix adoption
When sales teams do not use the CRM, the default assumption is usually attitude, discipline or resistance to process. Those factors can play a role, but they are rarely the root cause.
In most cases, low usage is a signal that the system does not match how work actually happens. When that gap exists, even well-intentioned teams will default to easier alternatives.
The sections below help you distinguish between behaviour problems and design problems, so you can fix the right thing.