Unable to connect to MySQL server (Docker)

I have set up a Docker container with a MySQL server running version 8.0.21 (also tried 8.0)

Whenever I try to connect to the database in Power BI Desktop I get the following error:

We encountered an error while trying to connect.

Details: "An error happened while reading data from the provider: 'Internal connection fatal error. Error state: 18'"

I also get this error while trying to connect to a MySQL server in Powe BI Desktop running on a Xampp installation.

I have tried to uncheck "Encrypt connections" in Data source settings. 

I can connect to the server via MySQL Workbench without any problems and I can also login via PhpMyAdmin running on the same instances. 

I have checked that my credentials and that I am using the correct ports etc.

I am running the latest version of Power BI Desktop.

Any clues?