The problem of frequent black screens on server VPS may be caused by a variety of factors. The following are some common causes and corresponding solutions:

　　Resource exhaustion: If the applications running on your VPS take up too much CPU, memory or disk resources, it may cause the system to become unstable or even black screen. The solution is to check system resource usage, optimize applications, or upgrade server configuration.

　　Operating system problems: A fault or misconfiguration of the operating system may cause a black screen. Try restarting the server, check the operating system logs for error messages, and make any necessary repairs.

　　Network problems: Network problems may cause the VPS to be unable to be accessed remotely, causing it to appear like a black screen. Make sure the server has a good network connection and check your firewall settings to make sure remote connections are not blocked.

　　Outdated or unstable virtualization technology: If the virtualization technology used by your VPS provider is unstable or outdated, it may cause a black screen issue. In this case, consider changing VPS providers or upgrading to more reliable virtualization technology.

　　Hardware problem: The black screen problem may also be caused by server hardware failure. If you have physical access, check the server's hardware status, including memory, hard drives, and power supplies.

　　Malware or viruses: A server infected with malware or viruses may cause instability and a black screen. Use security software to scan your server for potential threats and make sure the applications and services running on your server are up to date to fix known security vulnerabilities.

　　Remote connection problems: If you access the server through SSH or remote desktop, the problem may occur with the local computer or connection settings. Make sure your remote connection client is working properly and there are no configuration issues.

　　Logging and monitoring: Enabling detailed logging and monitoring on your server can help you diagnose problems more easily. Monitoring tools can help you monitor server performance and resource usage in real time, as well as detect any anomalies.

　　If you are unable to determine the cause of the black screen issue or cannot resolve the issue, it is recommended to contact your VPS provider or system administrator for professional help. They can assist you in further diagnosing the problem and taking appropriate steps to repair the server.