A Site That Went Nowhere How mychevrolettahoecom Got Stuck in a Redirect Loop

The microsite at mychevrolettahoe.com was supposed to be simple: a clean, campaign-specific landing destination that sales teams could print on window stickers, media buyers could paste into ad tags, and social teams could tuck behind short links. It carried a single job—collect interest in the Tahoe, showcase configurations, and pass qualified visitors into the main Chevrolet funnel. Instead, it became a quiet lesson in how a handful of tiny, independently sensible settings can combine into a perfect storm of redirect chaos, turning an otherwise routine launch into a multi-team scramble.

At the center of the problem was a host header and cookie mismatch that only surfaced under real-world traffic. The domain’s apex was set to 301 to the www host, a standard move meant to consolidate signals. The CDN property then forwarded the request to the Adobe Experience Manager origin that powered the campaign pages. That origin expected an authenticated session cookie, set on first hit at the root path and scoped to the mychevrolettahoe.com domain. But a parallel marketing platform rule—built to unify journeys across Chevrolet-owned properties—was configured to scope several tracking cookies at the parent brand level, chevrolet.com. The result was a subtle split-brain: the microsite’s gatekeeper looked for a session cookie it thought it had set, while the marketing layer set a different cookie on a different eTLD+1. Each saw the other as incomplete, and both politely tried to “help” by redirecting the visitor to a page that would fix the missing state. The browser obeyed, ping-ponging between the CDN and origin until Chrome threw up ERR_TOO_MANY_REDIRECTS.

That would have been bad enough, but a second rule made it worse. In a last-mile redirect worker, engineers added a convenience feature for analytics that appended a cmpid parameter if one was missing, defaulting to a campaign code so that untagged links would still be attributable. The condition checked for the presence of cmpid in a case-sensitive way. Some links came through with CMPID and others with cmpId. The worker didn’t recognize either as the same parameter and dutifully added another cmpid on top. Each redirect grew the query string, which preserved the entire prior query. Before the loop detector fired, the URL string sometimes ballooned past several kilobytes—long enough to trigger 414 URI Too Long at the origin for a subset of crawlers and a few enterprise proxies.

Where the loop manifested depended on device and path. Desktop browsers hitting the apex via http saw: apex to www via 301, CDN to /home via 302, origin back to / via 302 to set session, CDN tacking on cmpid, origin refusing to accept the brand-scoped cookie, CDN assuming there was still no attribution, and so on. Mobile traffic introduced a separate failure mode. The team had implemented an app-link fallback so that if the MyChevrolet app was installed, certain paths attempted to open a deep link to mychevrolet://tahoe. When that scheme was not registered, the script fell back to the web path—but because the deep link check lived behind the same cookie gate, it never progressed past the handshake. Some Android devices briefly flashed the app banner before yielding to a white screen as the loop spun.

Because everything looked fine in staging, the loop made it to production with fanfare. Staging used a different base domain and an allowlist of internal IPs; cookies there were scoped to the staging host, not the brand parent, so the mismatch never appeared. Uptime monitors greenlit the cutover; they followed a single, cached 200 from a known-good path that the CDN had quietly marked as always-fresh. The first alarm wasn’t a monitor—it was a social media manager posting a campaign link into a preview card tester and watching the card fail to resolve after following more than ten redirects. The second was paid search, where destination mismatch errors started appearing in the ad platform, halting a chunk of spend. Then came the field calls from dealers scanning snipe-label QR codes on showroom units and getting nowhere.

Debugging under load exposed the ripple effects. The SEO team saw search engine crawlers back off after repeated 3xx chains, with the microsite’s canonical tag never evaluated, leaving noindex directives from an earlier warmup state stuck in limbo. Analytics reported a jump in sessions with zero pageviews as beacons fired from intermediate responses rather than the final page. Email links that had been click-wrapped by the ESP added still another redirect hop, pushing some journeys over the threshold for corporate filters that cap chained redirects. A fraud-detection partner flagged the host as suspicious for “excessive redirection,” which in turn tripped a browser-integrated safe-browsing warning for a handful of users behind aggressive endpoint protection.

The root-cause workshop, convened in a rush, mapped the chain on a whiteboard with every layer labeled: registrar DNS with ALIAS flattening at the apex; CDN property rules enforcing HSTS and the apex-to-www move; redirect worker that normalized paths and query parameters; WAF policy that challenged a subset of traffic and performed a 302 to a validation path; the origin expecting a session cookie scoped to the microsite; the cross-site marketing script that set brand-scoped cookies; and the downstream app-link script with its own expectations. Every team owned a reasonable decision in isolation; together, the decisions formed a circuit.

The fix list was surgical but nontrivial. The cookie scope for the session was rewritten to the host-only domain and its lifetime extended to avoid “first-hit” loops, then the brand-scoped cookie logic was taught to gracefully degrade when the host didn’t match the eTLD+1 for chevrolet.com. The redirect worker’s parameter injector was made case-insensitive and idempotent; if cmpid existed in any case, it would not add another, and if it had to add the parameter, it would write a fresh location header rather than preserve a growing query string. The apex-to-www rule was simplified to include an early exit for the validation path used by the WAF so the challenge could complete in-place without bouncing the user. HSTS was retained, but preload aspirations were deferred until the team could guarantee that every subresource was available on the consolidated host. A single canonical URL was chosen, and the CDN was configured to return 200 for that path from cache even when the origin was slow to set state, ensuring that external monitors—and more importantly, social cards—would always resolve.

On the campaign mechanics side, the QR codes were quietly hot-fixed. A DNS-based steering record allowed mychevrolettahoe.com/qr to resolve to a static, loop-proof landing page on chevrolet.com with a content slot that mirrored the microsite hero, making sure in-store scanning worked even if the microsite faltered again. Paid media swapped to deep, absolute URLs on the consolidated host rather than the vanity domain for the remainder of the flight. The email team purged link shorteners that added unnecessary hops and updated the ESP click wrapper settings to “passthrough” for this host. Customer care received a one-paragraph macro with the correct URL and a brief explanation to defuse confusion from early visitors.

Postmortem metrics told an unflattering story but also showed how fast a disciplined rollback can recover a campaign. In the first forty-eight hours, bounce rates were artificially high and time-on-page collapsed; once the loop broke, both reverted to expected ranges, and dealers reported that the QR codes “magically started working again.” Search crawlers returned after the 3xx chains dropped below five hops, and the restored canonical helped reestablish the right snippet in brand queries within a week. The anti-fraud partner removed the “excessive redirect” flag after a re-crawl; the safe-browsing warnings disappeared as cached verdicts expired.

The lasting impact was organizational more than technical. The teams adopted a preflight that treats redirects as a first-class surface, not a footnote: a redirect budget baked into acceptance criteria, idempotency guarantees for parameter manipulators, an automated case-insensitive query sanitizer, and a synthetic monitoring check that navigates as a real user would—from apex and www, over http and https, with and without cookies, and from mobile and desktop user agents—while enforcing a hard cap on total redirect count. Staging was made more production-like by aligning cookie scopes and disabling internal IP shortcuts for a slice of traffic. App-link checks were decoupled from the cookie gate and built to fail closed to the web landing page rather than attempt a deep link while state was still being negotiated. Most importantly, ownership of the vanity domain moved under the same governance as the primary chevrolet.com host, eliminating the shadow rules that had accumulated to “make it work” across stacks.

From the outside, all a visitor ever saw was a browser error, a spinning loader, or a blank white page that resolved itself days later. Inside, the episode became a textbook reminder that microsites are not small sites; they are full sites routed through extra layers of indirection, and those layers multiply the cost of every assumption. mychevrolettahoe.com didn’t fail because of a single bad redirect. It failed because a dozen good intentions, each a few characters long, composed into a loop. That is the paradox of modern web delivery: the shortest path to nowhere is often paved with the smallest changes.

The microsite at mychevrolettahoe.com was supposed to be simple: a clean, campaign-specific landing destination that sales teams could print on window stickers, media buyers could paste into ad tags, and social teams could tuck behind short links. It carried a single job—collect interest in the Tahoe, showcase configurations, and pass qualified visitors into the main…