The value of
that you are trying to insert into the table
already exists on that table, and the column has a UNIQUE constraint on it.
Either remove the UNIQUE constraint (probably not the right solution) OR check for whether you should be updating an existing row or inserting a new one.
We cannot make that decision for you, nor can we help much beyond this unless you actually share more details of your code and database
Here are some references that may help:
Create Unique Constraints - SQL Server | Microsoft Docs
Unique Constraints and Check Constraints - SQL Server | Microsoft Docs
An Essential Guide to SQL Server UNIQUE Constraint
As you have tagged Jupyter you might get more information from there - see Project Jupyter | Home