When you encounter a "server proxy lookup failed" error, it means that the server proxy was unable to find the requested resource. This error typically occurs when a client, such as a web browser, sends a request to a server through a proxy server, and the proxy server is unable to fulfill the request.

There are several potential reasons why this error might occur:

1. Proxy Server Unavailable: The proxy server itself might be down or experiencing issues. This could be due to maintenance, network problems, or other technical issues.

2. Misconfigured Proxy Settings: The client's proxy settings might be misconfigured, leading to the request being sent to an incorrect or non-functioning proxy server.

3. Network Connectivity Issues: There could be network connectivity issues between the client, the proxy server, and the destination server. This could be due to network congestion, routing problems, or other network-related issues.

4. Firewall or Security Restrictions: The request might be blocked by a firewall or other security measures in place on the proxy server or the destination server.

5. DNS Resolution Problems: The proxy server might be unable to resolve the domain name of the requested resource, leading to the lookup failure.

When you encounter a "server proxy lookup failed" error, there are a few steps you can take to try and resolve the issue:

1. Check Proxy Server Status: If you have access to the proxy server, check its status to ensure that it is up and running properly.

2. Verify Proxy Settings: Double-check the proxy settings on the client to ensure that they are correctly configured.

3. Check Network Connectivity: Verify that there are no network connectivity issues between the client, the proxy server, and the destination server. You can do this by checking for any network outages or performing network diagnostics.

4. Review Firewall and Security Settings: If you have access to the proxy server or the destination server, review the firewall and security settings to ensure that they are not blocking the request.

5. DNS Troubleshooting: If the issue is related to DNS resolution problems, you can try using alternative DNS servers or troubleshooting DNS resolution on the proxy server.

If you are unable to resolve the "server proxy lookup failed" error on your own, you may need to reach out to your network administrator or IT support team for further assistance. They can help diagnose the issue and take appropriate steps to resolve it.

In conclusion, a "server proxy lookup failed" error indicates that the proxy server was unable to find the requested resource. By understanding the potential reasons for this error and taking appropriate troubleshooting steps, you can work towards resolving the issue and restoring normal network connectivity.