I have a MySQL database. When I try to test or connect the database I get error:Unauthorized. I am using OpenRefine 3.8.6 on Windows 10. The attached image illustrates how I am trying to create the connection to the database and the messege I get when I click on Connect.
Hi @Daniel_de_la_Osa and Welcome to 
OpenRefine!
Can you try troubleshooting by using the MySQL Workbench client and connect with the same user/password?
MySQL :: Download MySQL Workbench
Hi. Thank you for answer me so quickly. When I click on the link you gave me I see this message that I'm showing you in the attached image.
Just tried it and seems to work fine for me:
There are many clients out there to try and use, perhaps DBeaver and setup the connection and click it's Test button?