Your link does not work for me, but I found correct the link (forum.gl-internet.com in your link should be forum.gl-inet.com). The log messages look a little different (has “Detect rtchange event”, but no “flush one”):
As alzhao stated, the GL-MT1300 cannot detect Internet as ping cannot go through, probably due to you blocking Google. You can try a test by unblocking Google because the router may be cycling to attempt to restart the WAN connection.