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Troubleshooting UniFi Server Reject Issues

Published onby Dries (edited on )

At some point you'll like encounter a "Server Reject" error when attempting to adopt UniFi devices into the UniFi Controller.

This can be an annoying roadblock. The error indicates that the UniFi Controller has refused the adoption request from the device, preventing it from being managed within the network. Understanding the cause of this and how to resolve it is handy for maintaining your network efficiently.

In this article, I'll outline some common reasons for the "Server Reject" error and provides step-by-step troubleshooting strategies.

Let's dive in!

Table of Contents

Common causes of UniFi server reject

Let's first dive into the causes of the server reject error (because there are plenty of them):

  • Network Connectivity Issues: Problems with the network connection between the UniFi device and the Controller can lead to adoption failures.
  • Mismatched Inform URL: If the device is trying to connect to an incorrect or inaccessible Controller address, it can result in a "Server Reject" error.
  • Firewall or Security Settings: Overly restrictive firewall rules or security settings may block communication between the device and the Controller.
  • Device Firmware Outdated: Older firmware versions on the UniFi device may not be compatible with the version of the UniFi Controller.
  • Corrupted Controller Data: Sometimes, the UniFi Controller's data can become corrupted, leading to various issues including server rejections.

Troubleshooting steps

  1. Verify Network Connectivity: Ensure the UniFi device is correctly connected to the network and can reach the UniFi Controller. Check for any physical connectivity issues or misconfigurations in the network settings.

This seems straightforward, but often times this is the issues.

  1. Check the Inform URL: Confirm that the device's inform URL matches the address of your UniFi Controller. You can do this by accessing the device via SSH and using the set-inform command to view or set the correct URL.

  2. Review Firewall and Security Settings: Inspect your firewall and security settings to make sure they're not blocking traffic on ports required by the UniFi Controller (such as 8080, 8443, 3478, and others depending on your setup). Adjust the rules as necessary to allow communication between the device and the Controller.

  3. Update Device Firmware: If the device's firmware is outdated, update it to the latest version compatible with your UniFi Controller. This can often resolve compatibility issues leading to server rejection.

  4. Reset the UniFi Device: Performing a factory reset on the UniFi device can clear any corrupt settings that might be causing the issue. After resetting, attempt to adopt the device into the Controller again.

  5. Check Controller Health: Inspect the UniFi Controller for signs of corrupted data or operational issues. Restarting the UniFi Controller service or the server/host it runs on can sometimes resolve hidden issues.

  6. Inspect Controller Logs: The UniFi Controller logs can provide insights into why the server rejected the adoption request. Check the logs for any error messages or warnings that could indicate the cause of the problem.

How to fix

  • Adopt Using SSH: If the regular adoption process fails, try adopting the device using SSH. This method bypasses some of the common issues that can lead to server rejections.

  • Update the UniFi Controller: Ensure your UniFi Controller is up to date. Newer versions of the Controller software may contain fixes for bugs or compatibility issues that could be causing the server reject error. Here is how we do this at UniHosted

  • Re-Provision the Network: In cases where multiple devices or the entire network is affected, re-provisioning the network settings through the UniFi Controller can help resolve systemic issues.

Final thoughts

The "Server Reject" error can stem from multiple issues. Doing some troubleshooting will uncover the cause and helps to resolve the the underlying issue.

At UniHosted, we're more than happy to assist you with issues like this. Our cloud-hosted UniFi Controller services are designed to support easy device adoption and network management. We're all here for providing reliability and optimal performance to your UniFi networks.

Feel free to give us a spin! Additionally, I'm happy to walk you through personally. You can schedule a call with me (Founder of UniHosted) here.

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