Error map
ConnectionRefusedError [Errno 111] (SMTP) Python: ConnectionRefusedError: [Errno 111] Connection refused — smtplib connect to localhost:25
Email / SMTP · layer 2, Network
Centre: this error. First ring: errors it is linked with (9). 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 (9)
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.
Laravel: SQLSTATE[HY000] [2002] Connection refused (SQL: select * from sessions) / php_network_getaddresses: getaddrinfo failed
Laravel can't open a network connection to the database host and port from `.env`.
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…
Python: smtplib.SMTPServerDisconnected: Connection unexpectedly closed
The server closed the connection before your script finished the SMTP conversation — a timeout, blocked IP, TLS mismatch or rate…
PHP: sh: 1: /usr/sbin/sendmail: not found — mail() returns false
PHP's `mail()` calls the `sendmail_path` program, but it is not installed or the path in php.ini is wrong.
Laravel: Predis\Connection\ConnectionException: Connection refused [tcp://127.0.0.1:6379] / RedisException: Connection refused
Laravel can't connect to Redis, which it uses for cache, sessions or queues.
SMTP: telnet smtp.example.com 25 — Connection timed out (cloud provider blocks port 25)
Connections from your server to other mail servers on port 25 time out because your cloud host or ISP blocks outbound SMTP to fig…
Python: smtplib.SMTPAuthenticationError: (535, b'5.7.8 Username and Password not accepted')
`smtp.login()` was rejected by the server — wrong credentials, wrong password type, or authentication not allowed for that accoun…
Two steps away (26)
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…
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: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'x@example.com' for key 'users_email_unique'
The query violated a database constraint — a duplicate value in a unique column or a missing/blocked foreign key.
Laravel: SQLSTATE[HY000] [1045] Access denied for user 'forge'@'localhost' (using password: YES)
MySQL rejected the username/password configured in Laravel's `.env`.
Laravel: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'status' in 'field list'
The SQL refers to a column that doesn't exist in the table — a missing migration, typo or wrong table.
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 5.7.1 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…
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: 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.
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: [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…
SMTP: 504 5.5.2 <localhost>: Helo command rejected: need fully-qualified hostname
The receiving server refused your EHLO/HELO greeting because the name you sent is not a valid fully-qualified domain name.
PHP mail() returns false / emails not delivered
PHP’s mail() function failed or emails never arrive (spam or rejected).
WordPress: Your PHP installation appears to be missing the MySQL extension which is required by WordPress
PHP doesn’t have the mysqli extension loaded, so WordPress can’t talk to the database.
WordPress: Your server is running PHP version 7.2 but WordPress 6.x requires at least 7.4 / This plugin requires a newer version of PHP
WordPress core, a plugin or a theme needs a newer PHP than the server runs.
WordPress: Error establishing a Redis connection (object cache)
The persistent object cache drop-in (object-cache.php) can’t connect to Redis, so the whole site fails.
Laravel/PHP 8: ErrorException: Attempt to read property "name" on null
You accessed a property on a value that is `null`, typically an empty relationship or a query that found nothing.
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.
ssh: connect to host x port 22: Connection timed out
SSH packets get no reply — a firewall/security group drops them, the server is off, or the IP is wrong.
connect: No route to host (EHOSTUNREACH)
The destination host isn’t reachable — it’s down, on another subnet without routing, or a firewall rejects with “host unreachable…
Laravel: Symfony\Component\Mailer\Exception\TransportException: Connection could not be established with host "smtp.mailtrap.io:2525": stream_socket_client(): Unable to connect
Laravel's mailer could not connect to the SMTP host configured in `.env`.
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: 534-5.7.9 Application-specific password required. Learn more at https://support.google.com/accounts/answer/185833
The Google account has 2-Step Verification on, so SMTP clients cannot use the normal password; they need an app password (or OAut…
SMTP: 535-5.7.8 Username and Password not accepted. Learn more at https://support.google.com/mail/?p=BadCredentials
The server received your login but rejected it — wrong username or password, an unusable password type, or a blocked sign-in.
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