Hello,
Thanks for contacting us, and sorry for any inconvenience that might have been caused due to that.
This is a permission issue on your web server and to get around this issue we would recommend the following: https://rankmath.com/kb/cant-edit-robots-txt/#num-3-permission-issue-on-the-web-server
Hope that helps, and please do not hesitate to let us know if you need our assistance with anything else.
Thank you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.