Cannot change Server Base URL

[Vernon Song]

The Server Base URL field is greyed out and I cannot change.

I cannot even do this step - "uncheck the Enable check box next to Secure administrator sessions" in the security configuration from this link: - https://confluence.atlassian.com/display/DOC/Configuring+Secure+Administrator+Sessions

It just resets after I commit the change.

Any ideas?

[Nic Brough -Adaptavist-]

That's correct.  You can't just change the base url of a system to get it to be published on a different url.  You need to update all the DNS and network settings as well as the base url.

And you can't do any of that on Cloud.  To "change" the location of an Atlassian Cloud system, you have to buy a new one and migrate your data from the old to the new one.