Black screen after changes in config.edn

I have been using Logseq for a while with no problem. Today I made some changes in the config.edn within the default queries. Then when I restarted Logseq, I see some typical screens of Reloading, then the whole screen turns BLACK, with nothing. Even after I replaced with the previous config.edn, starting Logseq just gave me a BLACK screen. What can I do to get out of the BLACK screen? Appreciate any help.