---
title: Ontology Cell is Unavailable
description: "**ERROR MESSAGES** ***Ontology Cell is Unavailable*** # Possible Problems and Solutions: The following table is designed to assist you with troubleshooting this error. | When The Error Message Was Received | Possible Problem(s) | Possible Solution(s) | | --- |…"
url: "https://i2b2.org/docs/ontology-cell-is-unavailable/"
updated: "2026-09-15"
category: i2b2 Installation Guide / Chapter 7. Troubleshooting Installation Errors
---

# Ontology Cell is Unavailable

**ERROR MESSAGES**

***Ontology Cell is Unavailable***

# Possible Problems and Solutions:

The following table is designed to assist you with troubleshooting this error.

| When The Error Message Was Received | Possible Problem(s) | Possible Solution(s) |
| --- | --- | --- |
| Received while logged into the i2b2 Web Client or Workbench | The possible causes for this error message may be one of the following: - The Ontology Cell may not be deployed - The Ontology Cell may be down; the services are not running - The Ontology Cell may not be configured correctly in i2b2 Admin | - Verify the Ontology Cell was deployed by looking in the deployments folder located in ***YOUR_JBOSS_DIR*** - If the cell was deployed you will see a file called ont-ds.xml.deployed - If it was not deployed you won't see the above file and will need to deploy the ontology cell. - Check your web services to see if ***OntologyService*** is listed as active. If it is not then you need to restart JBoss. - Verify the Ontology Cell is configured correctly in i2b2 Admin. - The Cell Id should be ONT - The Cell URL should be the IP or domain name where the cell is located. |

# Installation Guide Resources:

The following resources address configuring deploying and configuring cells as well as checking web services.

| Resource For... | Chapter | Section |
| --- | --- | --- |
| Deploying the Ontology Cell | [Ontology Management (ONT) Cell Install](https://i2b2.org/docs/chapter-9-ontology-management-ont-cell-install/) | [Deployment](https://i2b2.org/docs/9-5-deployment/) |
| Checking Web Services | [Ontology Management (ONT) Cell Install](https://i2b2.org/docs/chapter-9-ontology-management-ont-cell-install/) | [Verify Ontology Installation](https://i2b2.org/docs/9-8-verify-ontology-installation/) |
| Stop Services | [Ontology Management (ONT) Cell Install](https://i2b2.org/docs/chapter-9-ontology-management-ont-cell-install/) | [Stop Services](https://i2b2.org/docs/9-3-stop-services/) |
| Start Services | [Ontology Management (ONT) Cell Install](https://i2b2.org/docs/chapter-9-ontology-management-ont-cell-install/) | [Start Services](https://i2b2.org/docs/9-6-start-services/) |
| Configuring Ontology Cell Data in i2b2 Admin | [Ontology Management (ONT) Cell Install](https://i2b2.org/docs/chapter-9-ontology-management-ont-cell-install/) | [Update ONT Cell Data in i2b2 Admin](https://i2b2.org/docs/9-7-update-ont-cell-data-in-i2b2-standalone-admin/) |
| Managing i2b2 Cells in i2b2 Admin | [Initial Setup of i2b2 in Admin](https://i2b2.org/docs/chapter-6-initial-setup-of-i2b2-in-admin/) | [Managing i2b2 Cells](https://i2b2.org/docs/6-4-managing-i2b2-cells/) |