Answer
Conversion rate optimization (CRO) fails when there is insufficient website traffic to generate statistically significant results, typically below 1,000 monthly visitors. It also fails without clear goals, poor data quality, or when changes are made based on opinions rather than testing.
CRO is not suitable for businesses with unstable traffic, incomplete tracking, or those prioritizing brand awareness over conversions. It can backfire if tests are too short, sample sizes are too small, or if winning variations are not implemented correctly. Companies without dedicated resources or leadership support often see stalled or inconsistent results.