Whenever you find that DSpace 7.x is acting up, it's best to use the Troubleshooting guide to look for underlying errors.
Sometimes you'll find that a simple misconfiguration or similar is to blame. Some of the common installation/configuration issues are listed in our install guide at:
As a sidenote, your backend logs do not show any errors (ERROR), so my suspicion is that there may be an error occurring in the frontend. Those errors are *only* visible in your browser's DevTools (see the troubleshooting guide) and will never appear in the backend logs.
Tim