There are some of the other ways you can try.
- First one is there is a hack, just append ?ToolPaneView=2 or ??ToolPaneView=2 to the end of the URL. See if you are able if not.
- Check and make sure that Publishing is turned off from the Site Features
- Third is checkout the page manually by by Navigate to Site Settings -> Site Content -> Site Pages -> Click on “…” next to page name -> Click on “…” -> Check out
Then try “Edit Page”