Support intro
Sorry to hear you’re facing problems 
help.nextcloud.com is for home/non-enterprise users. If you’re running a business, paid support can be accessed via portal.nextcloud.com where we can ensure your business keeps running smoothly.
In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
longer
example
here
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 20.0.5): replace me
Operating system and version (eg, Ubuntu 20.04): replace me
Apache or nginx version (eg, Apache 2.4.25): replace me
PHP version (eg, 7.4): replace me
The issue you are facing: Nextcloud randomly shows an error when I try to access it. “Error
It looks like you are trying to reinstall your Nextcloud. However the file CAN_INSTALL is missing from your config directory. Please create the file CAN_INSTALL in your config folder to continue.”
I am not trying to reinstall Nextcloud, I’ve just been using it normally for several months now. I was able to restore a backup on Linode to get rid of the error but it came back several hours later.
Is this the first time you’ve seen this error? (Y/N): Yes
Steps to replicate it:
The output of your Nextcloud log in Admin > Logging:
Can't Access (or I don't know how without logging into Nextcloud, Maybe SSH would work?
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
Not sure how to get that.
The output of your Apache/nginx/system log in /var/log/____:
Not sure how to get that.