MariaDB for remote connections

[Nace]

I added an IP to the MySQL database of user and remote access to MySQL database worked.
Recently I opened a new domain, created a new database, and added an IP I got an error on the client-side: Access denied for user.
How can I solve this problem? Any solution is very welcome.
I use MariaDB.

 

[Nace]

I add host (ip) here:
User Level -> MySQL Management -> databasename -> Add Access Host

For users who have added IP some time ago, it's work! But for new added IP doesn't work.

 

[Zhenyapan]

port 3306 must be opened in firewall

 

[Nace]

The port is opened, I can connect to MySQL database which was created in the past. I can not connect to the newly created.
If I delete IP from the old database and entered it again I can't establish a remote connection to this MySQL database again.