Setting up Master - Slave replication: error connecting to master (Error_code: 2003) I'm configuring this across two different servers on two different hosting companies.

Here is the tutorial I've followed for setting this up: https://www.digitalocean.com/community/tutorials/how-to-set-up-master-slave-replication-in-mysql

The master my.cnf settings are as follows: 

bind-address = 00.000.000.00
server-id = 1
log_bin = /var/log/mysql/mysql-bin.log
binlog_do_db = mydatabase


On the slave: 

server-id = 2
relay-log = /var/log/mysql/mysql-relay-bin.log
expire_logs_days = 10
max_binlog_size = 100M
binlog_do_db = mydatabase


Everything looks good until I try and check mysql&gt; SHOW SLAVE STATUS\G

*************************** 1. row ***************************
Slave_IO_State: Connecting to master
Master_Host: 000.000.000.00
Master_User: slave_user
Master_Port: 3306
Connect_Retry: 60
Master_Log_File:
Read_Master_Log_Pos: 4
Relay_Log_File: mysql-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File:
Slave_IO_Running: Connecting
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 0
Relay_Log_Space: 154
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 2003
Last_IO_Error: error connecting to master 'slave_user@000.000.000.00' - retry-time: 60  retries: 3
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 0
Master_UUID:
Master_Info_File: /var/lib/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp: 180104 23:22:36
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:


I've checked the error log as well and can see this: 

2018-01-04T23:05:10.948738Z 2 [ERROR] Slave I/O for channel '': error connecting to master 'slave_user@000.000.000.00:3306' - retry-time: 60  retries: 6, Error_code: 2003


I've checked the firewall and the port, which looks correct. I'm not sure what else I can check?
So, I actually had several issues that may come in handy to walk through for others:
Error: 2003
I removed the bind-address from the master
Errno: 1045
Access denied for user
I explicitly set the IP address for the slave user:
GRANT REPLICATION SLAVE ON *.* TO 'slave_user'@'000.000.000.00' IDENTIFIED BY 'password';
instead of
GRANT REPLICATION SLAVE ON *.* TO 'slave_user'@'%' IDENTIFIED BY 'password';
Error 1236
Got fatal error 1236 from master when reading data from binary log: 'log event entry exceeded max_allowed_packet
It turns out the default max_allowed_packet is 1MB for &lt;= 5.6.5 and 4MB for &gt;= 5.6.6.
I set both of these manually to 16MB as per this article
Error 1236
Got fatal error 1236 from master when reading data from binary log: 'bogus data in log event
I followed the instructions in this answer
That solved the last of my errors and the replication appears to be working as expected now!