Edit the value of TCAdmin.ConfigUtility.Database.ConnectionString in the master's /home/tcadmin/Monitor/ConfigUtility.config
If it is encrypted replace it with this:
<?xml version="1.0" encoding="utf-16" standalone="yes"?>
<values>
<add key="TCAdmin.ConfigUtility.Database.DBMS" value="MySql" type="System.String,mscorlib" />
<add key="TCAdmin.ConfigUtility.Database.Provider" value="TCAdmin.DatabaseProviders.MySql.MySqlManager,TCAdmin.DatabaseProviders.MySql" type="System.String,mscorlib" />
<add key="TCAdmin.ConfigUtility.Database.ConnectionString" value="Data Source=127.0.0.1;User Id=YOUR_DB_USER;Password=YOUR_DB_PASSWORD;Database=YOUR_DATABASE;" type="System.String,mscorlib" />
<add key="TCAdmin.ConfigUtility.Database.ConnectionString.Encrypted" value="False" type="System.Boolean,mscorlib" />
</values>