WordPress Multi Subsite not works

I activate this plugin in a subsite of wordpress multisite, however, the wp-admin page immediately broke and giving an error in the console: Refused to apply style from 'https://www.main.site/subsite/_static/?-eJx1kX0OwiAMxS8kQw9gPAsfVeooLGvZPL64xCUu9r++vPf4QbHrZLCE3CKwfbKVhGH09bUPQ2A+2Z5ykbDYrmyoRLUMXf4x73UmVrxtMgSlKYHoOPnq5qj4GVmMOJ9BQ0BEUawZFmSsRatS7zrFkwSkMp2vTYMWt2wP/u3uG/9Eup4qFoFZOWPF+ADR6IwCBoP6IflyLjrcN5HjSo63c02SCQnC+I3d6PoG1XDPyw==' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

How to fix this issue?
Thanks.