After Plesk panel upgrades to version 11.5, you may encounter this error while accessing the panel and it is due to the wrong reference to libmyodbc3.so as mySQL driver in odbcinst.ini. This can be corrected by following steps.
1) To find location of odbcinst.ini,
# /usr/bin/odbc_config --odbcinstini
/etc/odbcinst.ini
2) Check if /usr/lib64/libmyodbc5.so is installed in your server if not try "yum update mysqlclient15"
3) Update /etc/odbcinst.ini (or the one that '/usr/bin/odbc_config --odbcinstini' reports) replace any non-empty values of "Driver" and "Driver64" parameters (under section "[MySQL]") with /usr/lib64/libmyodbc5.so (or whatever you have installed).
4) # /etc/init.d/psa restart
Stopping sw-engine-fpm: [ OK ]
Starting sw-engine-fpm: [ OK ]
Bingo...!!
