MySQL connection error

When I try to start docker, and I cd into my presspack file and give the command "docker-compose up" it gives me errors.

`Starting presspack_db_1 ... done
Starting presspack_wordpress_1 ... done
Starting presspack_phpmyadmin_1 ... done
Attaching to presspack_db_1, presspack_wordpress_1, presspack_phpmyadmin_1
db_1 | 2018-10-10T01:29:33.760167Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
db_1 | 2018-10-10T01:29:33.765512Z 0 [Note] mysqld (mysqld 5.7.23) starting as process 1 ...
db_1 | 2018-10-10T01:29:34.137489Z 0 [Note] InnoDB: PUNCH HOLE support available
db_1 | 2018-10-10T01:29:34.139809Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
db_1 | 2018-10-10T01:29:34.141472Z 0 [Note] InnoDB: Uses event mutexes
db_1 | 2018-10-10T01:29:34.143867Z 0 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
db_1 | 2018-10-10T01:29:34.144729Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.3
db_1 | 2018-10-10T01:29:34.145656Z 0 [Note] InnoDB: Using Linux native AIO
db_1 | 2018-10-10T01:29:34.169431Z 0 [Note] InnoDB: Number of pools: 1
db_1 | 2018-10-10T01:29:34.690417Z 0 [Note] InnoDB: Using CPU crc32 instructions
db_1 | 2018-10-10T01:29:34.769451Z 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
db_1 | 2018-10-10T01:29:35.078961Z 0 [Note] InnoDB: Completed initialization of buffer pool
db_1 | 2018-10-10T01:29:35.301557Z 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
db_1 | 2018-10-10T01:29:35.418070Z 0 [Note] InnoDB: Highest supported file format is Barracuda.
db_1 | 2018-10-10T01:29:35.992180Z 0 [Note] InnoDB: Log scan progressed past the checkpoint lsn 2593926
db_1 | 2018-10-10T01:29:35.993621Z 0 [Note] InnoDB: Doing recovery: scanned up to log sequence number 2593935
db_1 | 2018-10-10T01:29:35.995253Z 0 [Note] InnoDB: Database was not shutdown normally!
db_1 | 2018-10-10T01:29:35.996587Z 0 [Note] InnoDB: Starting crash recovery.
db_1 | 2018-10-10T01:29:37.924679Z 0 [Note] InnoDB: Removed temporary tablespace data file: "ibtmp1"
db_1 | 2018-10-10T01:29:37.926746Z 0 [Note] InnoDB: Creating shared tablespace for temporary tables
db_1 | 2018-10-10T01:29:37.927767Z 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
db_1 | 2018-10-10T01:29:46.125970Z 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
db_1 | 2018-10-10T01:29:46.169664Z 0 [Note] InnoDB: 96 redo rollback segment(s) found. 96 redo rollback segment(s) are active.
db_1 | 2018-10-10T01:29:46.169879Z 0 [Note] InnoDB: 32 non-redo rollback segment(s) are active.
db_1 | 2018-10-10T01:29:46.175110Z 0 [Note] InnoDB: page_cleaner: 1000ms intended loop took 10874ms. The settings might not be optimal. (flushed=0 and evicted=0, during the time.)
db_1 | 2018-10-10T01:29:46.190378Z 0 [Note] InnoDB: 5.7.23 started; log sequence number 2593935
db_1 | 2018-10-10T01:29:46.203756Z 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
db_1 | 2018-10-10T01:29:46.522393Z 0 [Note] Plugin 'FEDERATED' is disabled.
db_1 | 2018-10-10T01:29:46.557444Z 0 [Note] InnoDB: Buffer pool(s) load completed at 181010 1:29:46
db_1 | 2018-10-10T01:29:46.809208Z 0 [Warning] Failed to set up SSL because of the following SSL library error: SSL context is not usable without certificate and private key
db_1 | 2018-10-10T01:29:46.832497Z 0 [Note] Server hostname (bind-address): '*'; port: 3306
db_1 | 2018-10-10T01:29:46.855514Z 0 [Note] IPv6 is available.
db_1 | 2018-10-10T01:29:46.859956Z 0 [Note] - '::' resolves to '::';
db_1 | 2018-10-10T01:29:46.870716Z 0 [Note] Server socket created on IP: '::'.
db_1 | 2018-10-10T01:29:47.390608Z 0 [Warning] Insecure configuration for --pid-file: Location '/var/run/mysqld' in the path is accessible to all OS users. Consider choosing a different directory.
db_1 | 2018-10-10T01:29:47.454565Z 0 [Warning] 'user' entry 'root@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.455937Z 0 [Warning] 'user' entry 'mysql.session@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.457772Z 0 [Warning] 'user' entry 'mysql.sys@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.463663Z 0 [Warning] 'db' entry 'performance_schema mysql.session@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.465065Z 0 [Warning] 'db' entry 'sys mysql.sys@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.470872Z 0 [Warning] 'proxies_priv' entry '@ root@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.521265Z 0 [Warning] 'tables_priv' entry 'user mysql.session@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.522535Z 0 [Warning] 'tables_priv' entry 'sys_config mysql.sys@localhost' ignored in --skip-name-resolve mode.
db_1 | 2018-10-10T01:29:47.994382Z 0 [Note] Event Scheduler: Loaded 0 events
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
phpmyadmin_1 | /usr/lib/python2.7/site-packages/supervisor/options.py:298: UserWarning: Supervisord is running as root and it is searching for its configuration file in default locations (including its current working directory); you probably want to specify a "-c" argument specifying an absolute path to a configuration file for improved security.
phpmyadmin_1 | 'Supervisord is running as root and it is searching '
phpmyadmin_1 | 2018-10-10 01:29:55,562 CRIT Supervisor running as root (no user in config file)
phpmyadmin_1 | 2018-10-10 01:29:55,566 INFO Included extra file "/etc/supervisor.d/nginx.ini" during parsing
phpmyadmin_1 | 2018-10-10 01:29:55,567 INFO Included extra file "/etc/supervisor.d/php.ini" during parsing
phpmyadmin_1 | Unlinking stale socket /run/supervisord.sock
phpmyadmin_1 | 2018-10-10 01:29:56,246 INFO RPC interface 'supervisor' initialized
phpmyadmin_1 | 2018-10-10 01:29:56,277 CRIT Server 'unix_http_server' running without any HTTP authentication checking
phpmyadmin_1 | 2018-10-10 01:29:56,280 INFO supervisord started with pid 1
phpmyadmin_1 | 2018-10-10 01:29:57,290 INFO spawned: 'php-fpm' with pid 14
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
phpmyadmin_1 | 2018-10-10 01:29:57,309 INFO spawned: 'nginx' with pid 15
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
wordpress_1 |
wordpress_1 | Warning: mysqli::__construct(): (HY000/1130): Host '172.20.0.3' is not allowed to connect to this MySQL server in Standard input code on line 22
wordpress_1 |
wordpress_1 | MySQL Connection Error: (1130) Host '172.20.0.3' is not allowed to connect to this MySQL server
presspack_wordpress_1 exited with code 1`

Start by running docker-compose up in the presspack directory and inspect the db and wordpress service output, focusing on MySQL error 1130: the WordPress container host is not allowed to connect. Compare the database and WordPress service configuration in the compose setup, and consider the issue done when the WordPress container starts without the repeated MySQL connection error.

Written by the indexing model from the issue text.