Web server changed. 525 error



My website is using Cloudflare. Yesterday I changed the web hosting from Amazon Lightsail to Transip. Now I get 525 error. I changed the IPs both on Transip setting and Cloudflare. What could be the problem?

The address of the website is: flexologic.nl

L.E.: I disabled the Cloudflare and the website is working, so i missed something, but I have no clue what.