The most common cause: it isn't actually no contact
Checking their social media daily, keeping the conversation alive through mutual friends, or replying “just this once” when they reach out all quietly undo the process while still feeling like you're “doing no contact.” The rule works because of consistency — partial versions of it don't produce partial results, they tend to produce close to none.
The intensity isn't dropping at all over several weeks
Some fluctuation is normal, but if the pull feels exactly as strong at week four as it did at day four, with zero relief on your hardest and easiest days alike, that's worth paying attention to — not as a personal failure, but as a signal you may need additional support beyond the app (a therapist, a support system) rather than just more time.
You're using it as a strategy aimed at them, not a recovery tool for you
If the entire plan is oriented around a hoped-for reaction from your ex rather than your own steadiness, it's easy to feel like it's “not working” simply because they haven't reacted the way you wanted — which was never a guaranteed outcome to begin with.
Consistency is the whole mechanism — make it easier to keep.
No Contact 40 Days' streak tracker and Rescue Mode exist specifically to make consistency easier to hold onto on the hard days.
Get the app on the App StoreCommon questions
Does one slip-up mean no contact isn't working?
No — a single relapse is information, not proof of failure. What matters more is the overall pattern over weeks, not any single day.
When should I consider getting outside support?
If the intensity genuinely isn't easing at all after several weeks, or if daily functioning (sleep, work, relationships) is seriously affected, that's worth bringing to a professional rather than waiting it out alone.
No Contact 40 Days is a personal-motivation and self-improvement tool. It is not therapy or medical or mental-health advice, and it is not a substitute for professional care. If you're struggling, please reach out to a qualified professional or a local support line.