Can't publish website via ftp with database publishing

I've build a website using Visual Studio 2019 that uses a SQL Server database. When I try to publixh it with FTP. When starting the website, I get following error message:

Security Exception

Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request failed.

When I try to use web deploy and I test my connection, I get following error message:

Web deployment task failed. (Could not connect to the remote computer ("windowsftp.webhosting.be"). On the remote computer, make sure that Web Deploy is installed and that the required process ("Web Management Service") is started.

Can someone help me?

Franky