MySQLWorkbench forward engineering error

I had the same problem, using version = 8.0.17.

The error originates when a relationship is formed if No action is selected in the "Foreign Key Options" section. Ensure that the Skip in SQL generation is checked (When No action is selected).

This should solve the problem!

MySQL Workbench is generating the script for MySQL 8 (which supports the new invisible indexes), which you likely do not have.

You need to specify the MySQL version you are using, either in Model\Model Options\MySQL\Target MySQL Version or, globally, in Edit\Preferences\Modelling\MySQL\Target MySQL Version.

Alternatively, you can go on the MySQL Workbench GUI, Edit->Preferences then Modeling->Mysql and change the default target MySQL.