Scytl’s own literature shows that they housed servers in Barcelona and Frankfurt.
See “scytl european parliament election night reporting 2019 pdf” at https://www.scytl.com/en/resource/european-parliament-elections-2019-success-case/
pg. 3: “To guarantee the success of this project, Scytl’s team began prepar-ing nine months in advance. Over this time, we conducted 3 sepa-rate trial runs, 5 user acceptance tests, and we set up the data collection center in Barcelona, as well as an emergency back-up center in Frankfurt.”