Error map
Laravel: Connection could not be established with host Laravel: Symfony\Component\Mailer\Exception\TransportException: Connection could not be established with host "smtp.mailtrap.io:2525": stream_socket_client(): Unable to connect
Email / SMTP · layer 2, Network
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
Laravel: 419 Page Expired (CSRF token mismatch)
Laravel rejected a POST because the CSRF token was missing, expired or didn’t match the session.
Laravel: No application encryption key has been specified.
Laravel’s APP_KEY is missing, so it can’t encrypt sessions and cookies.
Laravel: Target class [App\Http\Controllers\X] does not exist.
Laravel’s container couldn’t find the controller or class named in a route or binding.
Laravel: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'db.sessions' doesn't exist
Laravel queried a table that hasn’t been created — usually sessions, cache, jobs or a new model’s table.
Laravel: The stream or file "storage/logs/laravel.log" could not be opened in append mode: Failed to open stream: Permission denied
The web server can’t write to Laravel’s storage or bootstrap/cache directories.
Laravel: Vite manifest not found at: public/build/manifest.json
Laravel’s @vite directive can’t find the compiled asset manifest because assets weren’t built.
Nodemailer: Error: connect ETIMEDOUT 142.250.27.108:465 (code: 'ETIMEDOUT', command: 'CONN')
Nodemailer could not open a connection to the SMTP server before the timeout — a blocked port, wrong host, or network issue.
Nodemailer: Error: self signed certificate in certificate chain (code: 'ESOCKET') / unable to verify the first certificate
Nodemailer refused the SMTP server's TLS certificate because it is self-signed, expired, hostname-mismatched or missing its inter…
Laravel: Expected response code "250" but got code "550", with message "550 5.7.1 Relaying denied"
Laravel connected and authenticated but the SMTP server rejected the message at the RCPT TO / MAIL FROM / DATA step with the code…
Laravel/PHP: Allowed memory size of 134217728 bytes exhausted (tried to allocate 20480 bytes) in vendor/laravel/framework
A request (or artisan job) used more memory than PHP's `memory_limit` allows.
SMTP: 421 4.7.0 Our system has detected an unusual rate of unsolicited mail originating from your IP address. Mail sent from your IP address has been temporarily rate limited
The receiving server (often Gmail or Outlook) is temporarily throttling your mail because the volume or reputation of your sendin…
SMTP: 450 4.7.1 <user@example.com>: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/example.com.html
The recipient server deliberately rejected the first delivery attempt from an unknown sender (greylisting) and expects a legitima…
Two steps away (35)
HTTP 403 Forbidden
The server understood the request but refuses to authorize it — you (or the server process) are not allowed to access this resour…
Forbidden (403) CSRF verification failed. Request aborted.
Django rejected a POST because the CSRF token was missing, wrong, or the request origin isn’t trusted.
ASP.NET Core: The antiforgery token could not be decrypted / The required antiforgery cookie is not present (400 Bad Request)
Form POST failed antiforgery validation — the token is missing, the cookie is missing, or Data Protection keys changed so old tok…
Warning: file_exists(): open_basedir restriction in effect. File(/x) is not within the allowed path(s)
PHP is configured to access only certain directories, and the script tried to touch a file outside them.
PHP mail() returns false / emails not delivered
PHP’s mail() function failed or emails never arrive (spam or rejected).
PHP upload error 1: The uploaded file exceeds the upload_max_filesize directive in php.ini
The uploaded file is bigger than PHP’s upload_max_filesize, so PHP discarded it.
PHP Fatal error: Uncaught Error: Class "X" not found
PHP couldn’t load the class — autoloading failed, the namespace is wrong, or the dependency isn’t installed.
Laravel: Illuminate\Database\Eloquent\MassAssignmentException: Add [x] to fillable property to allow mass assignment
You passed an array to create()/update()/fill() containing a field that isn’t in the model’s $fillable list.
Laravel: Error: Class "App\Models\Post" not found
PHP can't find the class you referenced — a missing import, wrong namespace or file name, or a stale autoloader.
MySQL ERROR 1146 (42S02): Table 'db.table' doesn't exist
The query references a table that MySQL can’t find in that database.
MySQL ERROR 1022 (23000): Can't write; duplicate key in table
An ALTER/CREATE produced a duplicate key or constraint name — often a foreign key name that already exists in the database.
MySQL ERROR 1061 (42000): Duplicate key name 'x'
CREATE INDEX/ADD INDEX used an index name that already exists on the table.
Linux: Permission denied
Your user (or the service user) lacks read/write/execute permission on a file, directory or one of its parents.
Warning: include(x.php): Failed to open stream: No such file or directory
PHP couldn’t open a file for include/require/fopen — wrong path, missing file, or no permission.
Warning: session_start(): open(/var/lib/php/sessions/sess_x, O_RDWR) failed: Permission denied
PHP can’t write session files to the configured session.save_path.
COPY failed: file not found in build context / "/app/x": not found
The Dockerfile COPY refers to a path outside the build context, excluded by .dockerignore, or relative to the wrong directory.
Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain
The Gradle wrapper JAR (gradle/wrapper/gradle-wrapper.jar) is missing or corrupt.
Error: error:0308010C:digital envelope routines::unsupported
An old build tool (webpack 4, old react-scripts) uses a hash algorithm that OpenSSL 3 in Node 17+ disables.
Python: ConnectionRefusedError: [Errno 111] Connection refused — smtplib connect to localhost:25
Nothing is listening on the SMTP host and port your script connected to — often `localhost:25` because no host was given and no l…
Nodemailer: Error: Invalid login: 535-5.7.8 Username and Password not accepted (code: 'EAUTH', responseCode: 535)
The SMTP server rejected the credentials passed to Nodemailer.
Nodemailer: Error: Greeting never received (code: 'ETIMEDOUT', command: 'CONN')
The TCP connection was made but the server never sent its SMTP `220` banner — usually a TLS mode mismatch or a firewall/proxy swa…
SMTP: 530 5.7.0 Must issue a STARTTLS command first / 530 5.7.1 Authentication required
The server will not accept mail until you encrypt the connection (STARTTLS) and/or authenticate, and your client did neither.
SMTP: [SSL: WRONG_VERSION_NUMBER] wrong version number — SMTP over SSL on a STARTTLS port
Your client tried to start TLS immediately on a port where the server speaks plain SMTP first (or the reverse), so the handshake…
550 5.1.1 The email account that you tried to reach does not exist (User unknown)
The recipient mailbox doesn’t exist on the receiving server — a typo in the address, a deleted account, or a wrong domain.
550 5.7.1 Relaying denied / Message rejected as spam / Unauthenticated email not accepted
The receiving (or your outgoing) mail server refused the message — relaying isn’t allowed, the sender isn’t authenticated, or it…
SMTP: 451 4.3.0 Error: queue file write error / 451 Requested action aborted: local error in processing
The server hit an internal problem (disk, database, content filter, DNS) while handling your message and asked you to retry later.
PHP Fatal error: Allowed memory size of X bytes exhausted
The script tried to use more memory than PHP’s `memory_limit` allows.
Segmentation fault (core dumped)
A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).
Killed / Out of memory: Killed process (Linux OOM killer)
The kernel ran out of memory and killed a process to recover — the program just prints “Killed” (exit code 137).
WordPress / PHPMailer: SMTP Error: Could not authenticate / SMTP connect() failed
The SMTP server rejected the login or couldn’t be reached — wrong credentials, app passwords required, wrong port/encryption, or…
550 5.7.26 This mail has been blocked because the sender is unauthenticated (SPF/DKIM/DMARC)
Gmail/Outlook rejected the message because SPF and DKIM didn’t pass for the sender’s domain (DMARC failure).
SMTP: 452 4.2.2 The email account that you tried to reach is over quota
The recipient's mailbox has exceeded its storage quota, so the server will not accept new mail for now.
SMTP: 452 4.5.3 Your message has too many recipients / 452 Too many recipients received this hour
The server limits how many recipients a single message or sender may have; yours exceeded it.
SMTP: 552 5.3.4 Message size exceeds fixed maximum message size
The message, including attachments after base64 encoding, is larger than the receiving or sending server accepts.
SMTP: 550 5.7.1 Service unavailable; Client host [203.0.113.5] blocked using zen.spamhaus.org
The receiving server checked your IP in a DNS blocklist (Spamhaus, Barracuda, SORBS…) and refused your mail because it is listed.
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