As of 25 March 2021, Google safe browsing is incorrectly reporting that some sharefile.eu sites are suspected phishing sites. This also appears to affect Firefox for users with certain plugins enabled.
Citrix are actively working with Google to resolve the issue.
Note:- The error is only seen when using the Web interface. Citrix Files apps for Windows / macOS / mobile platforms are not affected. The plugins for Outlook are also not affected.