10 Daily Coding Errors Every Web Dev Faces (And How to Fix Them Fast)

PHPMailer, CORS, 404s, Eloquent N+1, and More – Real Fixes for Real Pain in 2025

Welcome back to The Web Developer's Journey! As a web developer in 2025, you're not alone if your day starts with a "Why isn't this working?!" moment. From PHPMailer silently failing to CORS blocking your API, these bugs waste hours—but they're fixable in minutes once you know the pattern.

This guide compiles the top 10 daily coding errors we all face—PHP, JavaScript, Laravel, Node.js, and more—with real-world causes, fixes, and prevention tips. Bookmark it. Share it. Save your sanity.

1

PHPMailer Not Sending Emails

Error: "Could not connect to SMTP host" or silent fail

80% of PHPMailer issues stem from SMTP config, SSL, or firewall blocks.

Common Causes & Fixes:

• Wrong Port/SSL: Gmail uses 465 (SSL) or 587 (TLS)
• App Password: 2FA on? Use 16-char app password, not account password
• Firewall: Allow outbound 465/587
• Debug Mode: Enable to see real error

use PHPMailer\PHPMailer\PHPMailer; $mail = new PHPMailer(true); $mail->SMTPDebug = 2; // Enable verbose debug $mail->isSMTP(); $mail->Host = 'smtp.gmail.com'; $mail->SMTPAuth = true; $mail->Username = 'you@gmail.com'; $mail->Password = 'your-app-password'; $mail->SMTPSecure = 'ssl'; $mail->Port = 465; $mail->setFrom('from@example.com', 'Name'); $mail->addAddress('to@example.com'); $mail->Subject = 'Test'; $mail->Body = 'Hello World'; try { $mail->send(); echo 'Sent!'; } catch (Exception $e) { echo "Failed: {$mail->ErrorInfo}"; }

Pro Tip: Use env('MAIL_MAILER', 'smtp') in Laravel with .env—never hardcode credentials.

2

CORS Blocking API Requests

Error: "Access-Control-Allow-Origin" missing

Frontend can't access backend? Browser blocks it for security.

Fixes:

• Laravel: Use fruitcake/laravel-cors middleware
• Node.js: Install cors package
• PHP: Add headers manually

// Laravel config/cors.php 'paths' => ['api/*'], 'allowed_methods' => ['*'], 'allowed_origins' => ['https://yoursite.com'], 'allowed_headers' => ['*'], 'supports_credentials' => true, // Node.js const cors = require('cors'); app.use(cors({ origin: 'https://yoursite.com' }));

Pro Tip: Use chrome --disable-web-security only for dev—never in production.

3

404 on Routes After Deploy

Error: Routes work locally, break on server

Apache? Nginx? .htaccess missing? Mod_rewrite off?

Fixes:

• Laravel: Point domain to public/ folder
• CodeIgniter: Upload .htaccess from public/
• Enable mod_rewrite: a2enmod rewrite && systemctl restart apache2

# Apache .htaccess in root (Laravel/CI) RewriteEngine On RewriteRule ^(.*)$ public/$1 [L]

4

Eloquent N+1 Query Hell

100 users = 100 DB queries

Slow pages? Check your loops.

Fix:

• Use with('relation')
• Enable query log: DB::enableQueryLog()
• Use Laravel Debugbar

// Bad $users = User::all(); foreach ($users as $user) { echo $user->profile->name; } // Good $users = User::with('profile')->get();

5

Composer Autoload Not Working

Class not found after adding new file

PSR-4 namespace mismatch?

Fix:

• Run composer dump-autoload
• Check composer.json autoload section
• Folder structure must match namespace

{ "autoload": { "psr-4": { "App\\": "app/", "Modules\\Blog\\": "modules/blog/src/" } } }

6

Session Not Persisting

Login lost after redirect

Session driver? Cookie domain?

Fixes:

• SESSION_DRIVER=file in .env
• Writable storage/framework/sessions
• Call session_start() in plain PHP

7

JavaScript Not Loading in Production

Works locally, blank in live

Cache? Path? Minification error?

Fixes:

• Hard refresh: Ctrl+F5
• Check view source for correct path
• Use asset() or Vite @vite

@vite(['resources/js/app.js'])

8

Database Connection Refused

"SQLSTATE[HY000] [2002] Connection refused"

Wrong host? Port blocked?

Fixes:

• DB_HOST=127.0.0.1 not localhost (sometimes)
• MySQL running? sudo service mysql start
• Allow port 3306 in firewall

9

Form Not Submitting (CSRF Token Mismatch)

419 Page Expired

Missing token in form?

Fix:

• Laravel: Add @csrf
• CI4:
• AJAX: Include X-CSRF-TOKEN header

@csrf

10

Cache Not Clearing

Old data still showing

Redis? File? Browser?

Fixes:

• php artisan cache:clear
• php artisan config:clear
• php artisan route:clear
• Hard refresh browser

# Clear all Laravel caches php artisan clear-compiled composer dump-autoload php artisan optimize:clear

Daily Dev Debug Toolkit (2025 Edition)

Laravel Debugbar

Real-time queries, logs, performance

Postman / Insomnia

Test APIs before frontend

VS Code + PHP Intelephense

Autofix namespaces, debug

Browser Dev Tools

Network tab = your best friend

Stop Wasting Hours on Repeat Bugs

These 10 errors hit every web dev daily—but now you have the fixes. Save this post. Print it. Tattoo it if you must.

Next time PHPMailer fails or CORS strikes, you'll fix it in 5 minutes, not 5 hours.

What’s your most hated daily bug? Comment below—let’s build the ultimate dev survival guide together!

From PHPMailer to CORS: Fix It Fast