


What to do if the email sending of Debian mail server fails
When the Debian mail server mail sending fails, you can follow the following steps to troubleshoot and resolve:
Check the mail server configuration
- Check the configuration file : Double-check the configuration file of the mail server, such as /etc/exim4/update-exim4.conf.conf, to ensure that the settings are correct.
- DNS resolution : Confirm that DNS resolution is normal, you can pass the telnet smtp.qq.com 25 command to test.
- Port Settings : Make sure that the SMTP port (usually 25) is open and not blocked by the firewall.
Check the email send log
- View log files : Check the log files of the mail server, such as /var/log/mail.log, for detailed error information.
Check the email blacklist
- Check the blacklist status : Confirm whether the email server is blacklisted, such as RBL (real-time black hole list), and process it as needed.
Check email size limit
- Resize emails : If the email is too large, it may cause the sending to fail. You can try to reduce the size of your email attachment.
Check the mail queue
- Clean up the email queue : If the email queue is blocked, it may affect the sending of the email. You can use the exim4 -bp command to view the queue and clean it up.
Check security policies
- Update security policy : Ensure that the security policies of the mail server such as SPF, DMARC, etc. are set correctly to allow legal mail to pass.
Restart the mail service
- Restart the service : After modifying the configuration file, make sure to restart the mail service for the changes to take effect. For example, use systemctl restart exim4.
Through the above steps, the problem of mail sending failure of Debian mail server can usually be solved. If the problem persists, it is recommended to view specific error information and seek help in the relevant community or forum.
The above is the detailed content of What to do if the email sending of Debian mail server fails. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

The best IDO platforms in 2025 are pump.fun, Bounce, Coin Terminal, Avalaunch and Gate Launchpad, which are suitable for Meme coin speculation, community-driven auctions, high-return pursuits, Avalanche ecological investment and fair participation of novices. The choice needs to combine investment goals, risk tolerance and project preferences, and focus on platform review and security.

In Binance spot trading, novices can earn their first profit by buying at low prices and selling at high prices. They need to master the basic operations such as trading pairs, stop-profit and stop-loss, and set up positions in batches. Combined with technical analysis and market observation, they can test the waters with small amounts of funds steadily, focus on risk control and fund safety, avoid full positions and follow-up operations, clearly calculate profits and losses through USDT pricing, and gradually accumulate experience to achieve continuous profits.

What is the directory DOT (Poker Coin)? The origin of Polkadot DOT (Polkadot) The operating principle of Polkadot has 5 major features, aiming to establish the Polkadot ecosystem (Ecosystem) 1. Interoperability 2. Scalability 3. Community Autonomy 4. No Fork Upgrade 5. NPOS Consensus Protocol Polkadot Key Features DOT Ecosystem Polkadot Vision: Connecting Everything Polkadot's Future Development Polkadot Price Forecast Polkadot 2025 Price Forecast Polkadot 2026-203

Cryptocurrency airdrop information aggregation websites include Airdrop Alert, One Click Airdrop Tracker, Free Airdrop.io and CoinMarketCap airdrop sectors. These platforms integrate full-network airdrop projects and provide functions such as classification screening, task guidance and participation progress tracking to help users efficiently obtain free tokens.

WLFI is a governance token for the LendFlare platform, built on Convex Finance to optimize revenue farming on Curve and Convex. Its price is affected by the overall market conditions of the crypto market, platform TVL, governance and pledge mechanism, supply and demand relationship and competitive environment. Investors can query real-time prices through platforms such as CoinGecko, CoinMarketCap or Uniswap, and then purchase USDT through mainstream exchanges such as Binance, OKX, and Huobi, and withdraw cash to a platform that supports WLFI transactions for redemption. Pay attention to network consistency and address accuracy during operation to avoid asset losses.

The crypto asset trading platform is a key hub connecting users and digital currencies. The article introduces mainstream global platforms such as Binance, OKX, gate.io, Huobi, KuCoin, Kraken, BITFINEX and Bitstamp. These platforms have performed outstandingly in terms of user volume, transaction volume, security, liquidity and service diversity, covering a variety of businesses such as spot, derivatives, DeFi, NFT, etc., meeting the needs of different users, and promoting the popularization and development of digital assets on a global scale.

WLFI tokens have not yet been confirmed to be launched on mainstream centralized exchanges. Investors need to verify their listing status through official channels or platforms such as CoinMarketCap and CoinGecko. If they are not launched, they may only trade on decentralized exchanges (DEXs) such as Uniswap and PancakeSwap. Users can connect to DEXs through Web3 storage such as MetaMask and enter the contract address obtained by the official to trade. Pay attention to slippage tolerance and security risks when operating; whether WLFI can be launched on a centralized exchange in the future depends on factors such as project fundamentals, community activity, liquidity and compliance. Project parties need to actively connect with the exchange and meet the review requirements, while Binance, OKX, Huobi

Cryptocurrency investment needs to combine fundamentals and capital flows: long-term investors should pay attention to fundamental factors such as project technology and teams to evaluate intrinsic value, while short-term traders can rely on capital flow data such as trading volume and capital flow to grasp market opportunities. The two are used complementary and refer to authoritative data sources such as CoinMarketCap and Glassnode, which can more effectively reduce risks and improve decision-making quality.
