When sending emails with SMTP, the user may encounter an error: "The SMTP server needs to be connected safely, or the client is not verified by identity. The server response is: 5.5.1 requires identity verification." This error is usually due to Google The identity verification problem or security measures implemented.
Reason:
Password error
access from third -party applications- Login attempts from different time zones/domain/equipment
- Solution:
Make sure the password entered in the code is correct.
Situation 2: Third -party application access
from
- Enable low security applications.
-
-
Situation 3: Log in from different time zones/domain/equipment
- Solution 1:
- Solution 2:
- (If you have the right to access the production server, you can use this method)
Log in from the production server browser to add an exception.
-
Visit https://www.php.cn/link/22cd4d66fc24fc0163ac00d27C1433C5 and click "Continue" to enable login from other time zones/IP.
The above is the detailed content of Gmail SMTP Error 5.5.1: How Can I Fix Authentication Issues?. For more information, please follow other related articles on the PHP Chinese website!

The main differences between C# and C are memory management, polymorphism implementation and performance optimization. 1) C# uses a garbage collector to automatically manage memory, while C needs to be managed manually. 2) C# realizes polymorphism through interfaces and virtual methods, and C uses virtual functions and pure virtual functions. 3) The performance optimization of C# depends on structure and parallel programming, while C is implemented through inline functions and multithreading.

The DOM and SAX methods can be used to parse XML data in C. 1) DOM parsing loads XML into memory, suitable for small files, but may take up a lot of memory. 2) SAX parsing is event-driven and is suitable for large files, but cannot be accessed randomly. Choosing the right method and optimizing the code can improve efficiency.

C is widely used in the fields of game development, embedded systems, financial transactions and scientific computing, due to its high performance and flexibility. 1) In game development, C is used for efficient graphics rendering and real-time computing. 2) In embedded systems, C's memory management and hardware control capabilities make it the first choice. 3) In the field of financial transactions, C's high performance meets the needs of real-time computing. 4) In scientific computing, C's efficient algorithm implementation and data processing capabilities are fully reflected.

C is not dead, but has flourished in many key areas: 1) game development, 2) system programming, 3) high-performance computing, 4) browsers and network applications, C is still the mainstream choice, showing its strong vitality and application scenarios.

The main differences between C# and C are syntax, memory management and performance: 1) C# syntax is modern, supports lambda and LINQ, and C retains C features and supports templates. 2) C# automatically manages memory, C needs to be managed manually. 3) C performance is better than C#, but C# performance is also being optimized.

You can use the TinyXML, Pugixml, or libxml2 libraries to process XML data in C. 1) Parse XML files: Use DOM or SAX methods, DOM is suitable for small files, and SAX is suitable for large files. 2) Generate XML file: convert the data structure into XML format and write to the file. Through these steps, XML data can be effectively managed and manipulated.

Working with XML data structures in C can use the TinyXML or pugixml library. 1) Use the pugixml library to parse and generate XML files. 2) Handle complex nested XML elements, such as book information. 3) Optimize XML processing code, and it is recommended to use efficient libraries and streaming parsing. Through these steps, XML data can be processed efficiently.

C still dominates performance optimization because its low-level memory management and efficient execution capabilities make it indispensable in game development, financial transaction systems and embedded systems. Specifically, it is manifested as: 1) In game development, C's low-level memory management and efficient execution capabilities make it the preferred language for game engine development; 2) In financial transaction systems, C's performance advantages ensure extremely low latency and high throughput; 3) In embedded systems, C's low-level memory management and efficient execution capabilities make it very popular in resource-constrained environments.


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