Ошибка установки MariaDB: Не мог исправить проблемы, Вы держали поврежденные пакеты

Я пытаюсь установить MariaDB после официального сайта, но я продолжаю получать ошибки.

Первый шаг:

$ sudo apt-get install software-properties-common
Reading package lists... Done
Building dependency tree       
Reading state information... Done
software-properties-common is already the newest version (0.96.24.32.5).
0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.

2-й шаг - Первая ошибка:

$ sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8
Executing: /tmp/apt-key-gpghome.aU8VMiqFGc/gpg.1.sh --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8
gpg: key F1656F24C74CD1D8: 5 signatures not checked due to missing keys
gpg: key F1656F24C74CD1D8: "MariaDB Signing Key <signing-key@mariadb.org>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1

3-й шаг - Это кажется прекрасным:

$ sudo add-apt-repository 'deb [arch=amd64,arm64,ppc64el] http://ftp.bme.hu/pub/mirrors/mariadb/repo/10.3/ubuntu bionic main'
Hit:1 https://mirrors.evowise.com/mariadb/repo/10.3/ubuntu bionic InRelease
Hit:2 http://ppa.launchpad.net/webupd8team/y-ppa-manager/ubuntu bionic InRelease                                                           
Hit:3 http://ftp.bme.hu/pub/mirrors/mariadb/repo/10.3/ubuntu bionic InRelease                                                              
Hit:4 http://ftp.bme.hu/pub/mirrors/mariadb/repo/10.1/ubuntu bionic InRelease                                                              
Hit:5 http://mirror.zol.co.zw/mariadb/repo/10.3/ubuntu bionic InRelease                                                                    
Hit:6 https://deb.nodesource.com/node_10.x bionic InRelease                                                                                
Hit:7 http://linux.teamviewer.com/deb stable InRelease                                                                                     
Hit:8 http://linux.teamviewer.com/deb preview InRelease                                                                                    
Ign:9 https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 InRelease                                                                 
Ign:10 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 InRelease
Hit:11 http://ftp.utexas.edu/mariadb/repo/10.3/ubuntu bionic InRelease
Hit:12 https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 Release
Hit:13 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 Release
Reading package lists... Done 

4-й шаг - Это прекрасно также:

$ sudo apt update
Hit:1 http://ftp.bme.hu/pub/mirrors/mariadb/repo/10.3/ubuntu bionic InRelease
Hit:2 http://ftp.bme.hu/pub/mirrors/mariadb/repo/10.1/ubuntu bionic InRelease                                                              
Hit:3 http://ppa.launchpad.net/webupd8team/y-ppa-manager/ubuntu bionic InRelease                                                           
Hit:4 https://mirrors.evowise.com/mariadb/repo/10.3/ubuntu bionic InRelease                                                                
Hit:5 http://linux.teamviewer.com/deb stable InRelease                                                                                     
Ign:6 https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 InRelease                                                                 
Hit:7 https://deb.nodesource.com/node_10.x bionic InRelease                                                                                
Hit:8 http://linux.teamviewer.com/deb preview InRelease                                                                                    
Ign:9 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 InRelease                                                                 
Hit:10 https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 Release                                                
Hit:11 http://ftp.utexas.edu/mariadb/repo/10.3/ubuntu bionic InRelease                         
Hit:12 https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 Release                      
Hit:13 http://mirror.zol.co.zw/mariadb/repo/10.3/ubuntu bionic InRelease 
Reading package lists... Done                      
Building dependency tree       
Reading state information... Done
All packages are up-to-date.

5-й шаг - Последняя ошибка:

$ sudo apt install mariadb-server
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 mariadb-server : Depends: mariadb-server-10.3 (>= 1:10.3.10+maria~bionic) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

Что вызывает эту ошибку? Действительно ли это - недостающий ключ в первой ошибке выше?

gpg: key F1656F24C74CD1D8: 5 signatures not checked due to missing keys
gpg: key F1656F24C74CD1D8: "MariaDB Signing Key <signing-key@mariadb.org>" not changed

Какие-либо идеи?