Location of your server isn't really important - check https://www.seroundtable.com/seo-geo-location-server-google-17468.html: "For search, specifically for geotargeting, the server's location plays a very small role, in many cases it's irrelevant. If you use a ccTLD or a gTLD together with Webmaster Tools, then we'll mainly use the geotargeting from there, regardless of where your server is located. You definitely don't need to host your website in any specific geographic location -- use what works best for you, and give us that information via a ccTLD or Webmaster Tools."
Similar message here: https://support.google.com/webmasters/answer/182192?hl=en:
- Server location (through the IP address of the server). The server location is often physically near your users and can be a signal about your site’s intended audience. Some websites use distributed content delivery networks (CDNs) or are hosted in a country with better webserver infrastructure, so it is not a definitive signal.
Specifically on CDN's - John Mu indicated
"At any rate, while moving to a CDN may result in small temporary fluctuations, making your site faster will frequently help your site much more. Some studies have shown that the faster your site is, the longer visitors will stay, and that's generally a good thing :-). As I mentioned above, if you're seeing significant changes in ranking, then I'd look for the issues elsewhere" (https://www.seroundtable.com/google-cdn-13117.html)
Dirk
