One: broken tracking tokens
A malformed or missing tracking parameter does not stop a campaign. It stops attribution, which means the campaign runs blind and later gets judged on a number that was never collected. Most commonly it is a stripped parameter after a redirect.
Prevention: click every live URL once, through the redirect chain, and confirm the parameter survives.
Two: pixels on the wrong page
A conversion pixel on the contact page rather than the thank-you page counts every visit as a conversion. Optimization then chases traffic that never converted, and it does so efficiently.
Prevention: fire a test conversion and verify the count moves by exactly one.
Three: naming convention drift
When campaign names are improvised, reporting cannot be rolled up, and nobody can find the campaign that needs pausing on a Friday afternoon. This looks cosmetic until an account has four hundred line items.
Prevention: a written convention, applied by template, not by memory.
Four: geography set wrong
The most expensive of the six for local advertisers. Radius targeting centered on a corporate address instead of the service area. Location "interest" targeting instead of physical presence. Statewide when the plan said county.
Prevention: verify the delivery map, in the platform, after launch — not the setting, the map.
Five: pacing left on defaults
Accelerated delivery spends a monthly budget in nine days, usually against the least qualified impressions available. It shows up as a great first week and a dead month.
Prevention: check spend on day three against the plan, every flight.
Six: incomplete creative sets
Missing sizes and aspect ratios mean placements silently go unfilled, so the channel appears to underperform when it was never fully in market.
Prevention: a per-channel asset matrix, checked before launch rather than after the first weak report.