Thank you for contacting Rank Math and sorry for any inconvenience that might have been caused due to that.
We might need to take a closer look at the settings. Please edit the first post on this ticket and include your FTP details in the designated Sensitive Data section.
It is completely secure and only our support staff has access to that section. If you want, you can use the below plugin to generate a temporary login URL to your website and share that with us instead: