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UTM parameters vanish when your site architecture drops query strings during redirects, transitions, or processing. The most common culprits are regional redirects, HTTPS enforcement, mobile site detection, and poorly configured URL shorteners. The Most Common Causes Regional and Mobile Redirects When users land on yoursite.com/?utm_source=facebook&utm_campaign=holiday but get redirected to us.yoursite.com or m.yoursite.com, many redirect configurations drop the query string entirely. The user arrives at the destination, but the attribution data is gone. HTTP to HTTPS Transitions Sites that redirect from HTTP to HTTPS can lose UTM parameters if the redirect rule doesn't explicitly preserve query strings. This is particularly common with older .htaccess configurations or misconfigured CDNs. URL Shorteners and Link Services Bit.ly, TinyURL, and custom shorteners can strip UTM parameters if not configured to preserve the full query string. Some tracking link services prioritize their own parameters and drop yours. CDN and Edge Configurations Content delivery networks that apply...