Connection troubleshooting

# Overview

The CKEditor Collaboration Server utilizes WebSockets connections to communicate with the CKEditor. WebSockets connections provide two-way communication between the editor and server. Such a connection is used to provide a real-time experience.

Another way CKEditor 5 communicates with external resources is by HTTPS connection. This mechanism is used to fetch a token from a token endpoint and upload and download images from CKBox service.

# Requirements

• WebSockets (port 443)
• HTTPS (port 443)

# Possible problems

# Restricted WebSocket connection

In case when the WebSocket connection is not possible, the user will receive an error with The number of initial connection attempt exceeded. message.

In such a case, please verify whether the CKEditor Collaboration Server is available from the user’s browser. It can be done by opening the default page of the server: for SaaS visit the Info Page page, for On-premises visit the https://{your_domain}/panel page and from the On-premises in version 4.5.0 the https://{your_domain}/ page.

If the page is available but the error still occurs then there is a possibility that the WebSocket connection in blocked on the user’s device or network level.

The WebSocket connection may be blocked in a few ways:

User level:

• antivirus software
• firewalls
• older browsers or outdated browser versions

Network level:

• firewall
• router configuration
• Internet provider restrictions

Please verify that none of above things blocks the WebSocket connection. It is possible you will need to contact your system and network administrator. If the problem with WebSocket connection still occurs, feel free to contact us.