My guess is that you are not checking the following from this guide, which states that you can't use
Declared and initialized in the same statement (inline initialization). SSMS will not parameterize variables declared using separate SET statements.
I get the same error you get when I write code like what you have in the question. This is why we ask for the code that breaks, not the code that works (though I doubt the code you wrote in your question works either!):
DECLARE @column nvarchar(30);
SET @column = N'whatever';
It works just fine when I declare the variable and assign it immediately, like this:
DECLARE @column nvarchar(30) = N'whatever';
This mismatch can happen for a variety of other reasons, of course. Such as not setting your connection to
column encryption setting = enabled, not enabling the "Enable Paramterization..." setting in SSMS, using a function or expression when declaring and assigning the variable, using the wrong data type or length or precision or scale, etc. We could help narrow that down if you include the code that breaks.