Hier das log-file: (sagt mir nicht wirklich etwas was auf den Fehler hinweist, daher alles von eben):
2020-04-25 10:53:31 0 [Note] InnoDB: Using Linux native AIO
2020-04-25 10:53:31 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2020-04-25 10:53:31 0 [Note] InnoDB: Uses event mutexes
2020-04-25 10:53:31 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2020-04-25 10:53:31 0 [Note] InnoDB: Number of pools: 1
2020-04-25 10:53:31 0 [Note] InnoDB: Using SSE2 crc32 instructions
2020-04-25 10:53:31 0 [Note] mysqld: O_TMPFILE is not supported on /tmp (disabling future attempts)
2020-04-25 10:53:31 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2020-04-25 10:53:31 0 [Note] InnoDB: Completed initialization of buffer pool
2020-04-25 10:53:31 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2020-04-25 10:53:32 0 [Note] InnoDB: 128 out of 128 rollback segments are active.
2020-04-25 10:53:32 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2020-04-25 10:53:32 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2020-04-25 10:53:32 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2020-04-25 10:53:32 0 [Note] InnoDB: Waiting for purge to start
2020-04-25 10:53:32 0 [Note] InnoDB: 10.4.12 started; log sequence number 1693888; transaction id 10176
2020-04-25 10:53:32 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2020-04-25 10:53:32 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-04-25 10:53:32 0 [Note] InnoDB: Buffer pool(s) load completed at 200425 10:53:32
2020-04-25 10:53:33 0 [Note] Server socket created on IP: '127.0.0.1'.
2020-04-25 10:53:34 0 [Note] Reading of all Master_info entries succeeded
2020-04-25 10:53:34 0 [Note] Added new Master_info '' to hash table
2020-04-25 10:53:34 0 [Note] /usr/sbin/mysqld: ready for connections.
Version: '10.4.12-MariaDB-1:10.4.12+maria~bionic' socket: '/var/run/mysqld/mysqld.sock' port: 3306 mariadb.org binary distribution
2020-04-25 10:56:13 0 [Note] /usr/sbin/mysqld (initiated by: unknown): Normal shutdown
2020-04-25 10:56:13 0 [Note] Event Scheduler: Purging the queue. 0 events
2020-04-25 10:56:13 0 [Note] InnoDB: FTS optimize thread exiting.
2020-04-25 10:56:13 0 [Note] InnoDB: Starting shutdown...
2020-04-25 10:56:13 0 [Note] InnoDB: Dumping buffer pool(s) to /var/lib/mysql/ib_buffer_pool
2020-04-25 10:56:13 0 [Note] InnoDB: Buffer pool(s) dump completed at 200425 10:56:13
2020-04-25 10:56:15 0 [Note] InnoDB: Shutdown completed; log sequence number 1693897; transaction id 10177
2020-04-25 10:56:15 0 [Note] InnoDB: Removed temporary tablespace data file: "ibtmp1"
2020-04-25 10:56:15 0 [Note] /usr/sbin/mysqld: Shutdown complete
2020-04-25 10:56:15 0 [Note] InnoDB: Using Linux native AIO
2020-04-25 10:56:15 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2020-04-25 10:56:15 0 [Note] InnoDB: Uses event mutexes
2020-04-25 10:56:15 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2020-04-25 10:56:15 0 [Note] InnoDB: Number of pools: 1
2020-04-25 10:56:15 0 [Note] InnoDB: Using SSE2 crc32 instructions
2020-04-25 10:56:15 0 [Note] mysqld: O_TMPFILE is not supported on /tmp (disabling future attempts)
2020-04-25 10:56:15 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2020-04-25 10:56:15 0 [Note] InnoDB: Completed initialization of buffer pool
2020-04-25 10:56:15 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2020-04-25 10:56:15 0 [Note] InnoDB: 128 out of 128 rollback segments are active.
2020-04-25 10:56:15 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2020-04-25 10:56:15 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2020-04-25 10:56:15 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2020-04-25 10:56:15 0 [Note] InnoDB: 10.4.12 started; log sequence number 1693897; transaction id 10176
2020-04-25 10:56:15 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-04-25 10:56:15 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2020-04-25 10:56:15 0 [Note] Server socket created on IP: '127.0.0.1'.
2020-04-25 10:56:15 0 [Note] InnoDB: Buffer pool(s) load completed at 200425 10:56:15
2020-04-25 10:56:15 0 [Note] Reading of all Master_info entries succeeded
2020-04-25 10:56:15 0 [Note] Added new Master_info '' to hash table
2020-04-25 10:56:15 0 [Note] /usr/sbin/mysqld: ready for connections.
Version: '10.4.12-MariaDB-1:10.4.12+maria~bionic' socket: '/var/run/mysqld/mysqld.sock' port: 3306 mariadb.org binary distribution
2020-04-25 11:00:59 8 [Warning] Access denied for user 'otmar'@'localhost' (using password: NO)
2020-04-25 11:01:23 9 [Warning] Access denied for user 'otmar'@'localhost' (using password: NO)
2020-04-25 11:01:32 10 [Warning] Access denied for user 'root'@'localhost' (using password: NO)
2020-04-25 11:02:13 11 [Warning] Access denied for user 'otmar'@'localhost' (using password: NO)
2020-04-25 11:11:15 0 [Note] /usr/sbin/mysqld (initiated by: unknown): Normal shutdown
2020-04-25 11:11:15 0 [Note] Event Scheduler: Purging the queue. 0 events
2020-04-25 11:11:15 0 [Note] InnoDB: FTS optimize thread exiting.
2020-04-25 11:11:15 0 [Note] InnoDB: Starting shutdown...
2020-04-25 11:11:15 0 [Note] InnoDB: Dumping buffer pool(s) to /var/lib/mysql/ib_buffer_pool
2020-04-25 11:11:15 0 [Note] InnoDB: Buffer pool(s) dump completed at 200425 11:11:15
2020-04-25 11:11:16 0 [Note] InnoDB: Shutdown completed; log sequence number 1693906; transaction id 10177
2020-04-25 11:11:16 0 [Note] InnoDB: Removed temporary tablespace data file: "ibtmp1"
2020-04-25 11:11:16 0 [Note] /usr/sbin/mysqld: Shutdown complete
2020-04-25 11:13:23 0 [Note] InnoDB: Using Linux native AIO
2020-04-25 11:13:23 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2020-04-25 11:13:23 0 [Note] InnoDB: Uses event mutexes
2020-04-25 11:13:23 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2020-04-25 11:13:23 0 [Note] InnoDB: Number of pools: 1
2020-04-25 11:13:23 0 [Note] InnoDB: Using SSE2 crc32 instructions
2020-04-25 11:13:23 0 [Note] mysqld: O_TMPFILE is not supported on /tmp (disabling future attempts)
2020-04-25 11:13:23 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2020-04-25 11:13:23 0 [Note] InnoDB: Completed initialization of buffer pool
2020-04-25 11:13:23 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2020-04-25 11:13:23 0 [Note] InnoDB: 128 out of 128 rollback segments are active.
2020-04-25 11:13:23 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2020-04-25 11:13:23 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2020-04-25 11:13:23 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2020-04-25 11:13:23 0 [Note] InnoDB: Waiting for purge to start
2020-04-25 11:13:23 0 [Note] InnoDB: 10.4.12 started; log sequence number 1693906; transaction id 10176
2020-04-25 11:13:23 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2020-04-25 11:13:23 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-04-25 11:13:23 0 [Note] InnoDB: Buffer pool(s) load completed at 200425 11:13:23
2020-04-25 11:13:23 0 [Note] Server socket created on IP: '127.0.0.1'.
2020-04-25 11:13:23 0 [Note] Reading of all Master_info entries succeeded
2020-04-25 11:13:23 0 [Note] Added new Master_info '' to hash table
2020-04-25 11:13:23 0 [Note] /usr/sbin/mysqld: ready for connections.
Version: '10.4.12-MariaDB-1:10.4.12+maria~bionic' socket: '/var/run/mysqld/mysqld.sock' port: 3306 mariadb.org binary distribution