The error message, then the cause, then the fix.
No generic "try a proxy" advice. Each page starts from the exact error, separates platform policy from technical failure, and says when to stop patching and switch routes.
Amazon 503 Service Unavailable
HTTP 503 from Amazon product pages usually means automated traffic is being throttled. The official affiliate and seller APIs, and when a hosted public-data tool is the better route.
Product Advertising API is deprecated
Calls to Amazon's PA-API 5 now return 403 AccessDenied. What changed, how the Creators API that replaces it differs, and why old keys stop working.
403 Forbidden with cf-mitigated
A 403 from a site behind Cloudflare is either a challenge page or a block rule. How to tell which one you got, what Cloudflare documents as the causes, and how clearance works.
Google Maps 120-result limit
Google Maps list views stop returning places and the official Places API caps Text Search at 60 results. Learn why the ceiling exists and how to split an area into complete coverage.
REQUEST_DENIED and OVER_QUERY_LIMIT in the Google Places API
What the two Places API status codes mean, the billing and key problems behind them, and the legacy API changes that make old projects and new projects behave differently.
Instagram 429 Too Many Requests
HTTP 429 on Instagram means the request was throttled. Meta's Graph API uses specific throttle codes instead of documenting 429. Here is how to tell them apart and back off correctly.
HTTP 999 from LinkedIn
LinkedIn answers some scripted page requests with status 999, a code outside the HTTP standard. What it signals, what LinkedIn's terms say and what the official API does offer.
LinkedIn authwall
A LinkedIn authwall redirect is an access restriction, not a bug. What LinkedIn's terms allow, why Proxycurl was shut down, and the routes that remain for company and public data.
Reddit .json 403 Forbidden
Why unauthenticated Reddit .json requests return 403, which deadlines apply to RSS and the public API, and the compliant routes for public post data.
Reddit RSS shutdown
Reddit stops supporting RSS feeds on November 13, 2026. The authenticated migration routes, moderator exception and what has no official replacement.
429 Too Many Requests on the X API
A 429 from the X API means either a per-endpoint rate limit or the monthly usage cap was hit.
This content isn't available, try again later
This YouTube error means the session or account went over YouTube's video request rate limit.
quotaExceeded
The YouTube Data API returns 403 quotaExceeded when a project uses up its daily quota.
Sign in to confirm you’re not a bot
YouTube asks some sessions to sign in before it serves a video. What the yt-dlp error means, the documented request limits.
YouTube transcript RequestBlocked
Third-party transcript endpoints get RequestBlocked. The official captions API only works for videos you can edit. Here is the accurate split between official and hosted routes.
Zillow 403 Forbidden
A Zillow 403 is an access denial, not a data format problem. See Zillow's official partner route, the legal constraints around listing data, and the hosted public-data alternative.