iPython shell freezes when hitting tab to autocomplete

I'm using ipython(from Anaconda3) shell on a remote Linux machine. Today, When I hit tab to autocomplete something, the ipython shell just freezes.

Also, I found this issue only happens when I type something then hit the tab, if there is an empty line, hitting tab just gives 4 spaces as usual.

This problem just arose today never happened before.

I googled this problem but didn't find the exact same situation. Happy to see some recommends.

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