PhpStorm cannot connect to the remote MySQL database - Codes Helper

set up a Linux server (Ubuntu 18.04) in Linode. Using PhpStorm to connect remotely has been a failure, and attempts to retrieve various scenarios have been fruitless. Please help me a lot. Thank you!

the settings are as follows:

system log:

2018-05-24 15 Terminating: 4791/RemoteDriverImpl42c8892f 19Terminating: 4791/RemoteDriverImpl42c8892f 27640 [26377197] INFO-ution.rmi.RemoteProcessSupport-Terminating: 4791/RemoteDriverImpl42c8892f
2018-05-24 15 INFO-ution.rmi.RemoteProcessSupport-Process finished with exit code-1
2018-05-24 15 INFO 19773 [26377530] INFO-ution.rmi.RemoteProcessSupport-"C:Program FilesJetBrainsPhpStorm 2018.1.3jre64binjava"-Djava.net.preferIPv4Stack=true-Djava.rmi.server.hostname=127.0.0.1-Duser.timezone=UTC-Dfile.encoding=UTF-8- Classpath "C:Program FilesJetBrainsPhpStorm, January 3, 2018, libutil.jar; C:Program FilesJetBrainsPhpStorm January 3, 2018.3 libtrove4j.jarterCist Program FilesJetBrainsPhpStorm FilesJetBrainsPhpStorm 2018.1.3libgroovyKuallmi 2.4.12.jarentCren Program FilesJetBrainsPhpStorm 2018.1.3pluginsDatabaseToolslibjdbcMube FilesJetBrainsPhpStorm 2018.1.3pluginsDatabaseToolslibdekafsingleMuture2.0.353.jarX CRAX Userswill.PhpStorm2018.1configjdbcdbcdriversMySQL 2018.1configjbjcdriversMySQL 2018.3libtrove4j.jarm2018.1pluginsDatabaseToolslibjdbcdriversMySQL 2018.3pluginsDatabaseToolslibdekafsingleMutual C:Userswill.PhpStorm2018.1configjdbc-driversMySQL ConnectorJ5.1.46mysql-connector-license.txt "com.intellij.database.remote.RemoteJdbcServer com.mysql.jdbc.Driver
2018-05-24 15 INFO 28148 [26377705] INFO-ution.rmi.RemoteProcessSupport-Terminating: 11026/RemoteDriverImplb9d224e3
2018-05-24 15 INFO 19149 [26377706] INFO-ution.rmi.RemoteProcessSupport-Terminating: 6614/RemoteDriverImpla46c136f
2018-05-24 15 15 INFO 28169 [26377726] INFO-ution.rmi.RemoteProcessSupport-Process finished with exit code-1
2018-05- 24 1515 INFO-ution.rmi.RemoteProcessSupport-Process finished with exit code-1
2018-05-24 15V 19Vl28318 [26377875] INFO-ution.rmi.RemoteProcessSupport-Port/ID: 15700/RemoteDriverImpl9af1f66f
2018-05-24 15VOF 19VO28 337 [26377894] INFO-urce.DatabaseConnectionManager-Connecting as: will
2018-05-24 15VOG 19VG 28337 [26377894] INFO-urce.DatabaseConnectionManager-Connecting to: jdbc:mysql:// . . * .121: 3306/elvis_store
2018-05-24 1515 WARN 48934 [26398491] WARN-urce.DatabaseConnectionManager-Connecting to: jdbc:mysql:// . . * .121: 3306/elvis_store
2018-05-24 15V 1948 934 [26398491] WARN-urce.DatabaseConnectionManager-[08S01] Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
2018-05-24 15 WARN 1948 935 [26398492] WARN-lij.database.util.ErrorHandler-Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
java.sql.SQLException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:342)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2188)
at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2037)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2021)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:776)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
at com.intellij.database.remote.jdbc.impl.RemoteDriverImpl.connect(RemoteDriverImpl.java:27)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:346)
at sun.rmi.transport.Transport$1.run(Transport.java:200)
at sun.rmi.transport.Transport$1.run(Transport.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Caused by: java.net.ConnectException: Connection refused: connect

at java.net.TwoStacksPlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:301)
... 30 more