1. Network connection problem: If there is a problem with network connection, you may not be able to browse the website information normally or the page will load slowly.

2. Browser settings: Some browser settings may affect the display effect of web content, such as disabling JavaScript and Cookie.

3. Server maintenance: In order to upgrade, maintain and optimize the performance of the website, the website administrator sometimes needs to temporarily shut down the website or some functions, resulting in visitors not being able to use the service normally.