Failed to Run Localhost because of Run Time Error

I'm getting runtime error whenever I run the localhost. Redis was running but it only loaded the homepage. After about 10 seconds, the server stopped and gave us this error.

`__connect_nonblock': Operation now in progress - connect(2) would block (IO::EINPROGRESSWaitWritable)

I was able to test successfully before, I don't know why it's not working now.
Can someone please help out? Thank You!