Error Loggs Database Problem?

Hey Everbody,

after i tried a nextcloudpi on my pi, i fully installed a Ubuntu18.04-LAMP (Apache2, PHP7.2, MariaDB 10.1.44) on a external hoster.
Now i’m done but i habe some issues and und errors in my Admin-Logs:

Doctrine\DBAL\Exception\DriverException: An exception occurred while executing ‘SELECT uid, displayname FROM oc_users u LEFT JOIN oc_preferences p ON (userid = uid) AND (appid = ‘settings’) AND (configkey = ‘email’) WHERE (uid COLLATE utf8mb4_general_ci LIKE ?) OR (displayname COLLATE utf8mb4_general_ci LIKE ?) OR (configvalue COLLATE utf8mb4_general_ci LIKE ?) ORDER BY uid_lower ASC LIMIT 500 OFFSET 500’ with params ["%%", “%%”, “%%”]: SQLSTATE[42000]: Syntax error or access violation: 1253 COLLATION ‘utf8mb4_general_ci’ is not valid for CHARACTER SET ‘utf8’

I think its the MariaDB that generate these problems.

In the official Manuel:
https://docs.nextcloud.com/server/16/admin_manual/configuration_database/linux_database_configuration.html

They Write:

Your /etc/mysql/my.cnf could look like this:…

But in my case there are only a Default-Text:

The MariaDB configuration file…

And when i’m running maintenance:repair i get 3 Error-Messages:

An exception occurred while executing ‘ALTER TABLE oc_addressbooks CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb
4_bin;’:

SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes

In PDOStatement.php line 119:

SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes

In PDOStatement.php line 117:

SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes

Could anyone help?

Is it possible to repair the Database or install just the Database new without the rest?
There are no files on the cloud yet. What is the best way to troubleshoot this?

What have you done? Was it possible for you to run the web based installed and create an user? Did you create a new database? How did you create that database?

Your link is to an old version of manual, replace 16 with 19 or 20