Symptoms
- 
After importing a WordPress instance from another server to Plesk, the website shows characters such as  â. For example:This isâthe website content. 
- 
The following line is present in the domain's wp-config.phpfile in Plesk > Domains > example.com > File Manager:define('DB_COLLATE', ''); 
Cause
Incorrect collation on some tables in the domain's database.
The Charset and Collation from the WordPress instance database example_db are set as follows:
#  plesk db
MariaDB [psa]> use example_db;
MariaDB [example_db]> SELECT @@character_set_database, @@collation_database; 
+--------------------------+----------------------+ 
| @@character_set_database | @@collation_database | 
+--------------------------+----------------------+ 
| utf8 | utf8_general_ci | 
+--------------------------+----------------------+
There are tables in the example_db database with a different collation than the one above, for example:
#  plesk db -ne"SHOW TABLE STATUS FROM example_db" | grep latin
table1 ... latin1_swedish_ci
table2 ... latin1_swedish_ci
Resolution
- 
Go to Domains > example.com > File Manager. 
- 
Open the wp-config.phpfile and comment out the lines below by putting//at the beginning of the line as follows://define('DB_COLLATE', ''); 
 ...
 //define('DB_CHARSET', 'utf8');