What may be causing the 404 statuses is "slasharguments" not working. There's at least one forum thread where the poster couldn't get this working with InMotion Hosting. This is an issue with the configuration of the web server and best addressed to InMotion's support. Moodle's use of slasharguments can be turned off by adding $CFG->slasharguments = 0 to config.php. It will probably allow this page to load correctly. It's probably worth doing as it would confirm that this is the problem.
However, turning off slasharguments in Moodle is not recommended and some functionality (notably SCORM activities) will not work without it. The best approach would be to have slasharguments supported by the web server. IONOS hosting has a similar problem and there are some steps in the docs for this. I don't know if they apply to InMotion too.