Fixing Issue on PKP Open Journal System Script

Fixing Issue on PKP Open Journal System Script

I have updated "PKP Open Journal System" (pkp ojs) from the version 2.x to 3.01, after updating have got some issues...
1. Users are unable to login with their existing credentials
2. Unable to view my Articles in PDH/html versions on the browser. attached the screenshot.

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Requirements

I need to fix this issue as soon as possible.
Main script available here https://pkp.sfu.ca/ojs/

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Skills Required

Php Mysql Html Js