Google Does Not Index / Traffic Drops After Migrate

When you "move house" (change theme/CMS, domain, URL structure, server), Google needs time to re-crawl the data. If the migration process lacks steps, two common risks are not indexed (or slow indexing) and traffic loss. This article is a practical playbook: systematic diagnosis, priority treatment P1–P3 and 2–8 week recovery roadmap.

If you need a clear P1 "firefighting" plan framework (SLA, responsible person, action checklist), please refer to Tan Phat Digital's pillar article on Ho Chi Minh website maintenance to understand the actual rescue process: Ho Chi Minh website maintenance service.

1) Identify the problem: what are you experiencing?

Common symptoms

• Many new URLs do not appear on Google even though the sitemap has been submitted.

• GSC reports a sudden increase Crawl anomalies / 404 / 5xx / Soft 404 / Alternate page with proper canonical.

• Impressions/clicks dropped sharply in Search Results.

• The home page went up but the money pages (category, product, pillar articles) disappeared.

• Index "wrong" version (www vs non-www, http vs https, yes/no trailing slash).

3 quick locating questions

1. What changed during the migration? (domain, path, server, CMS, render)

2. Is the redirect map (301 map) complete?

3. What is the status of robots, meta robots, canonical, hreflang, sitemap?

2) 90-minute diagnostic box (priority P1 first)

P1 — Block bots, switch wrong direction, server error

• robots.txt: definitely no Disallow: / or blocking important folders.

• Meta robots / money pages must pay 200, avoid duplicate 302, 5xx.

• Canonical: self-canonical, do not point to the wrong staging/old version.

• Redirect map 301: from any old URL → corresponding new URL, do not drop 404/soft 404, no 301 string.

• Sitemap: contains only URL 200–indexable–canonical; parameter type/staging/trash tag.

P2 — Google doesn't understand the new structure

• Internal link: menu, breadcrumb, link in updated article? Are there orphaned pages after migration?

• Hreflang (multilingual): right-way pair, self-include, standard area code.

• Pagination/faceted: filter for unlimited URLs? Block crawls properly (robots/noindex/URL params).

• Render: SPA/JS renders late? Check View source & Test live URL (GSC).

P3 — Quality & speed signals

• Core Web Vitals: Bad LCP/INP/CLS after changing theme/CDN.

• Schema: lost Organization, Breadcrumb, Article/Product.

• Entity/brand: domain/logo/sameAs are inconsistent.

3) Priority troubleshooting checklist

A. Required (P1) – Processing within 24–48 hours

1. Unblock index: fix robots.txt, remove erroneous noindex.

2. Fix redirect map: make a list of old URLs → 301 1–1 to the new closest URL, avoid chains/loops repeat.

3. Canonical: self-canonical, unified https + www/non-www + slash.

4. Clean Sitemap: URL only 200–indexable–canonical; If changing domain, use Change of Address in GSC.

5. Fix 5xx/timeout: stabilize server, CDN/WAF, don't block bots with captcha on public page.

Lack of manpower or need a technical team on P1 immediately 24 hours? You can quickly start Tan Phat Digital's Web Maintenance Services package to be assigned shifts, handle P1–P2 according to clear SLA: Web Maintenance Services.

B. Important (P2) – During weeks 1–2

6. Internal linking: update menu/breadcrumb, add link to important landing.

7. Hreflang: x-default pair, standard language code.

8. Google notification: Inspect URL → Request indexingfor ~50–100 pillar URLs; resubmit sitemap.

9. Crawl budget: reduce link depth, fix errors in bulk to speed up crawling.

C. Improvement (P3) – Parallel 2–6 weeks

10. Speed/CWV: lazy-load images, compress/critical CSS, defer JS, CDN/cache.

11. Schema & E-E-A-T: Organization, Breadcrumb, Article/Product, author, reference source.

12. Brand signals: update domain/logo/sameAs consistently; PR prompts new domain.

4) Recovery roadmap 2–8 weeks

• Week 0–1: patch P1, submit sitemap, request indexing money pages; Monitor GSC every 48 hours.

• Weeks 2–3: Complete P2 (internal link, hreflang, pagination, render). Traffic started to recover on the main page group.

• Weeks 4–6: P3 optimization (CWV, schema, content refresh). Impressions increase first, clicks recover after 1–2 weeks.

• Weeks 6–8: stable; do post-mortem & finalize pre-migration SOP. To reduce the risk of "migrate next time", see more monthly SOPs (periodical maintenance, checking for recurring errors) in Tan Phat Digital's article monthly website maintenance process: Monthly website maintenance process month.

5) "Invisible killers" after migration

• Staging indexed → set password/noindex, block robots.

• Loss of Search Intent due to changing content structure → refresh according to new SERP.

• Split/merge category but not getting the correct 301 → distributed signal.

• Multilingual format change without updating hreflang/schema.

• UTM parameter URL component → duplicate/soft 404 generation.

• Login wall/anti-bot on needed page index.

6) Sample “301 map” (principle 1–1)

• /blog/seo-onpage-2023 → /vi/blog/huong-dan-seo-onpage-chuan-google-2025/

• /dich-vu/thiet-ke-website.html → /dich-vu/thiet-ke-website/

• URL no longer has a purpose → 301 to most relevant parent page (don't put everything on the home page).

7) "Firefighting" process when traffic drops sharply

1. Zone by URL group (brand, category, money pages, pillar).

2. So SERP: competitors change format (video/PAAs/review)? Update content module to match.

3. Refresh content TOP falling page: 2025 data, real photos/cases, add FAQ/comparison table/schema.

4. Increase internal link coverage: descriptive anchor, block “related articles”.

5. Track 14–28 days, prioritize revenue generating pages first.

8) SOP before–during–after migration

Before: full crawl/export, create redirect map 1–1, staging test, freeze code 48h.
In: deploy redirect/robots/sitemap simultaneously; smoke test home/cate/PDP/pillar; Turn on log & monitor 5xx.
After (week 1–2): submit sitemap, request indexing money pages, fix 404/soft404/5xx in batch, adjust title/meta according to CTR.

9) Necessary tools & habits

• Google Search Console: Indexing report, Page inspection, Sitemaps, Removals.

• GA4: Organic sessions, landing pages, migration date annotation.

• Crawler (Screaming Frog/Website Auditor): compare before–after status, detect 404/redirect loop.

Patch promptly.

• Rollback data & code to the most recent stable version, keep the old redirect map intact to avoid "twisting" the signal.

• Plan the migration according to SOP, fully test staging.

11) Frequently Asked Questions (FAQ)

How long will the index be stable after migration?
Usually 2–6 weeks if the technique is clean, the redirect map is standard. Changing domains + large structures can take 8–12 weeks.

Should you "shoot" Request Indexing for thousands of URLs?
No need. Prioritize only 50–100 potential URLs; The rest is for Google to collect through sitemap & internal links.

Is a traffic drop of 20–30% normal?
Usually seen in the first 1–2 weeks. If it exceeds 50% and lasts >3 weeks, there is a high possibility that there is an unresolved P1/P2 error.

Should the old version be blocked with 410 instead of 301?
Only use 410 for content that is truly permanently deleted without a suitable replacement page. With migration, 301 1–1 is the norm.

Migrate doesn't kill SEO — lack of SOP is the culprit. Just go in the correct order P1 (blocking/direction/5xx) → P2 (structure & signal) → P3 (speed & quality), Google will understand your "new home" and return a ranking. If you need a "firefighting" team to review, create redirect map, clean sitemap/robots, restore index & traffic, Tan Phat Digital team has standard procedures, clear SLA and weekly reports so you can operate with peace of mind.