Hello! Please ensure that you use the latest version of Org Chart. Then, try to open the same page in private mode, all extensions should be switched off. If the issue persists, collect the data for research in the following order:
open a SharePoint page without the Org Chart web part in private mode,
open the developer tools (F12), switch to the "Network" tab and press Ctr+R,
add the Org Chart web part, start its configuration and reproduce the issue,
after that, save the HAR file (in Chrome, it is a button with the arrow down),
switch to the "Console" tab and save all logs,
send the collected information to support@plumsail.com, in your message, refer to this topic, specify the browser you used and its version.