Client sent an HTTP request to an HTTPS server

Issue Description

When accessing Portainer via the web you may receive the following error message:

Client sent an HTTP request to an HTTPS server.

Cause

This error occurs when you attempt to access Portainer's HTTPS URL (port 9443) using the HTTP protocol:

http://my.portainer.url:9443/

This is because port 9443 only accepts the HTTPS protocol and does not accept HTTP requests.

Resolution

Use the HTTPS protocol in the address when accessing port 9443.

https://my.portainer.url:9443/

Alternatively if you have HTTP access enabled you can access via HTTP on port 9000:

http://my.portainer.url:9000/