Submitting claim for cancelation

Hi, I want to request compensation under EU Regulation 261/2004 for cancellation of my flight that was 4d ago.

I am using the form (https://www.flysas.com/NL-en/customer-service/contact/forms/claim-flights/) , when I click submit the websites glitches and just says: "something went wrong"

Is there any other way legally acceptable to submit the claim?