Problems passing data from Plugin to Webservice since changing to HTTPS

Hi

I have a plugin that fires on Update and sends data through a webservice to update an external MSsql db.
All was fine but the project was parked for a while.

I've since gone back to it and now there's an issue with no data apparently getting to the webservice.

The only change to the system is that the Webservice now runs over httpS where as before when it worked it was http.

Would this cause my problem and if so how can I fix?

The parameterized query '(@FirstName nvarchar(4000),@LastName nvarchar(4000),@Email nvarc' expects the parameter '@FirstName', which was not supplied.