A bug, an error, an emergency ?
we handle it today.
500 error, blank page, broken checkout, hacked site, slow store, failed update : every page below matches a specific problem we handle every week. You describe what you see, we take over.
Your PrestaShop store is down ?
Identify your issue below. Each page describes the exact symptoms, the typical technical root causes and our intervention method.
PrestaShop 500 error
HTTP ERROR 500 on the front or back-office. We identify the root cause (memory_limit, .htaccess, fatal hook) and bring the site back online within the hour.
PrestaShop white screen
Store displaying a fully blank page, front or admin. Debug mode activation, identification of the faulty module or override, restoration with no data loss.
View page →PrestaShop unreachable
Timeout, ERR_CONNECTION, lost DNS, host down, MySQL crash : we test DNS / network / web server / database to identify the layer that has failed.
Slow PrestaShop store
Load time > 3 s, degraded Core Web Vitals, sluggish cart. Costed audit, prioritised levers (cache, database, modules, hosting), measurable gain within 30 days.
View page →PrestaShop cart / checkout bug
Cart emptying itself, looping step, failed payment, lost orders : full audit of the funnel, fast fix, calculation of recovered revenue.
View page →PrestaShop payment bug
Stripe failing, PayPal looping, 3DSv2 declined, Apple Pay invisible, webhook stuck : every PSP has its typical failures, we know them.
View page →PrestaShop back-office locked out
Forgotten admin URL, lost password, blank screen after login, 403, redirect loop : we recover access via SSH or phpMyAdmin.
View page →Failed PrestaShop migration
A 1.7→8 or 8→9 migration that broke everything : fatal modules, blank back-office, SEO collapse. Post-migration audit + step-by-step recovery prioritised by criticality.
View page →Urgent PrestaShop troubleshooting
Every type of emergency : site offline, blocking bug, lost access, host outage. Intervention within 30 minutes during business hours.
View page →PrestaShop maintenance
Monthly contract with no commitment : 24/7 monitoring, daily backups, security hotfixes, included dev time. From €50/month excl. VAT.
View page →Your WordPress site has an issue ?
Critical error, hack, malware, slowness, WooCommerce payment failing : here are our intervention pages.
“There has been a critical error”
The most common WordPress error message. Recovery mode, identification of the guilty plugin, restoration in under an hour.
View page →Hacked WordPress
Defaced site, suspicious redirects, compromised admin accounts. Full clean-up, security hardening, post-incident audit.
View page →WordPress malware removal
Site blacklisted by Google, redirects to pharmacy/casino sites, injected PHP code, ghost admins : full clean-up + hardening + monitoring.
View page →Slow WordPress
LCP > 3 s, sluggish WooCommerce, slow admin, heavy plugins : 8 levers (cache, DB, HPOS, CDN, plugins), typical gain −61 % LCP in 30 days.
View page →WooCommerce payment stuck
Order status “Pending” forever, Stripe webhook returning 403, customer paid but no order created, HPOS breaking everything : we plug it back in.
View page →WooCommerce unreachable
WC store completely down, timeout, WP-Admin unreachable, saturated MySQL, wp_options blowing up : SSH profiling and restart.
WordPress site recovery
Lost site, wiped database, host crash, failed migration : we explore the 4 sources (host/plugin backups, Google cache, Wayback Machine, server logs). Best-effort guarantee.
View page →Beyond troubleshooting : expertise and ongoing support
Need an expert for a project, recurring support or an SLA on-call ? These 3 pages cover the engagement models.
Certified PrestaShop expert
PrestaShop CORE SKILLS certification, 6+ years, 120+ stores. Custom development, audit, migration, optimisation. Direct contact, no agency middleman.
View page →PrestaShop support
4 modes : pay-as-you-go hourly, hour packs with volume discounts (5h/10h), monthly subscription, or SLA on-call. You pick what matches your pace.
View page →PrestaShop emergency
Emergency hotline : reply < 30 min during business hours, same-day intervention for 80 % of cases. Optional 24/7 SLA on-call for high-revenue stores.
View page →Always the same method, whatever the bug
No improvisation. Every KLN-WEB intervention follows these 4 steps — whether it's a 500 error, a hack or a broken cart.
Free diagnostic
You describe what you see. We look at the site, the accessible logs, and identify the error zone. No commitment, no invoice.
Quote within 24 business hours
Estimated time, hourly rate announced upfront (from €60/h excl. VAT). You know what you pay before we touch the site.
Intervention & fix
Systematic backup beforehand, intervention on staging when possible, validated deploy. You're kept informed at every step.
Post-mortem report
Root cause identified, fix documented, recommendation to prevent a recurrence. That's our signature.
Your issue isn't on the list ?
Describe it in 30 seconds, we get back to you within 24 business hours with a first diagnostic. No commitment, no sales pitch.