Why does the front page suddenly fail to open ，the error is console log like image before
Your version is past EOL. You should upgrade to either the latest version or the current LTS at your earliest convenience. Your upgrade path is:
7.9.7-> 8.9.10 → 9.9
You may find the Upgrade Guide and the LTS-to-LTS Upgrade Notes for 7.9 to 8.9, as well as the LTS to LTS release upgrade notes for 8.9 to 9.9 helpful. If you have questions about upgrading, feel free to open a new thread for that here.
If your error persists after upgrade, please come back to us.