@santhoshm687661 ,
Could you check your custom servlet which is implemented for QR code generation. I see there is some issue with servlet implementation QRCodeImagegenerator and Workflow process for deactivate.
Please make sure to check your error log.
1. Try to open we-retail site and if the pages looks good on we-retail system wise configs and bundles looks good.
2. Next check is your custom code and verify error log and project spefipic log files. if any unresolved dependencies please install external jar files or add them in the maven pom.xml.
Hope this help you in identifying the issue.
Thanks!!