Error: "Couldn't set ssl mode"

Question

I'm trying to set the SSL Mode in my connection string:

SSL Mode=preferred;

But I'm getting an ArgumentException when my code tries to connect to the database:

Notice that the InnerException, says:

Requested value 'preferred' was not found.

Looking at the following documentation, it should be valid to specify required, disabled or preferred:

• Npgsql Connection String Parameters
• Npgsql Security and Encryption

I'm using Npgsql 3.0.3, which I obtained using NuGet:

Answer 1

So it turns out that you actually need to specify verb values rather than adjectives:

• Disable
• Prefer
• Require

For example:

SSL Mode=Prefer;

Edit: the documentation has since been corrected.

Answer 2

Add sslmode=Require; and Trust Server Certificate=true; as it is in your connection string.It will work for sure.