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): 21.1.1
Operating system and version (eg, Ubuntu 20.04): docker
Apache or nginx version (eg, Apache 2.4.25): nginx
PHP version (eg, 7.4): 8.0.10
The issue you are facing:
failed to convert database from sqlite to mariadb.
Is this the first time you’ve seen this error? (Y/N):Yes
Steps to replicate it:
- exec in the nextcloud container
- run the convert command
- get the fail message
The output of your Nextcloud log in Admin > Logging:
In ExceptionConverter.php line 114:
An exception occurred while executing a query: SQLSTATE[HY000]: General error: 1366 Incorrect string value: '\xF0\x9F\x94\x96 D...' for column 'file' at row 1
In Exception.php line 26:
SQLSTATE[HY000]: General error: 1366 Incorrect string value: '\xF0\x9F\x94\x96 D...' for column 'file' at row 1
In Statement.php line 92:
SQLSTATE[HY000]: General error: 1366 Incorrect string value: '\xF0\x9F\x94\x96 D...' for column 'file' at row 1