What errors are you getting? Anything from the server log? You can go to Monitor > Logs to check out the errors.

INFO 02 Aug 2020 16:38:48 org.joget.apps.workflow.security.WorkflowAuthenticationProvider - jwc_rushiharal7 : Authentication for user manisha (27.106.116.235) : true
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INFO 02 Aug 2020 16:38:52 org.joget.workflow.shark.WorkflowAssignmentManager - jwc_rushiharal7 : [processId=111_cotten_procrument_process1, processDefId=cotten_procrument#8#process1, participantId=bracnh, next user=[manisha, rushikesh, virat]]
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INFO 02 Aug 2020 16:38:52 org.joget.apps.app.lib.UserNotificationAuditTrail - jwc_rushiharal7 : Users to notify: [manisha, rushikesh, virat]
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INFO 02 Aug 2020 16:40:04 org.joget.workflow.shark.WorkflowAssignmentManager - jwc_rushiharal7 : [processId=111_cotten_procrument_process1, processDefId=cotten_procrument#8#process1, participantId=bracnh, next user=[manisha, rushikesh, virat]]
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INFO 02 Aug 2020 16:40:04 org.joget.apps.app.lib.UserNotificationAuditTrail - jwc_rushiharal7 : Users to notify: [manisha, rushikesh, virat]
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INFO 02 Aug 2020 16:40:09 org.joget.workflow.shark.WorkflowAssignmentManager - jwc_rushiharal7 : [processId=111_cotten_procrument_process1, processDefId=cotten_procrument#8#process1, participantId=ho, next user=[ho]]
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INFO 02 Aug 2020 16:40:09 org.joget.apps.app.lib.UserNotificationAuditTrail - jwc_rushiharal7 : Users to notify: [ho]
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INFO 02 Aug 2020 16:40:34 org.joget.apps.workflow.security.WorkflowAuthenticationProvider - jwc_rushiharal7 : Authentication for user akola (27.106.116.235) : true
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INFO 02 Aug 2020 16:44:50 org.joget.apps.app.service.AppDevUtil - jwc_rushiharal7 : Commit to Git repo by akola: Update form entry_from. _
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INFO 02 Aug 2020 16:46:24 org.joget.apps.workflow.security.WorkflowAuthenticationProvider - jwc_rushiharal7 : Authentication for user virat (27.106.116.235) : true
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INFO 02 Aug 2020 16:46:28 org.joget.workflow.shark.WorkflowAssignmentManager - jwc_rushiharal7 : [processId=112_cotten_procrument_process1, processDefId=cotten_procrument#8#process1, participantId=bracnh, next user=[manisha, rushikesh, virat]]
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INFO 02 Aug 2020 16:46:28 org.joget.apps.app.lib.UserNotificationAuditTrail - jwc_rushiharal7 : Users to notify: [manisha, rushikesh, virat]
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INFO 02 Aug 2020 16:46:55 org.joget.workflow.shark.WorkflowAssignmentManager - jwc_rushiharal7 : [processId=112_cotten_procrument_process1, processDefId=cotten_procrument#8#process1, participantId=bracnh, next user=[manisha, rushikesh, virat]]
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INFO 02 Aug 2020 16:46:55 org.joget.apps.app.lib.UserNotificationAuditTrail - jwc_rushiharal7 : Users to notify: [manisha, rushikesh, virat]
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INFO 02 Aug 2020 16:46:59 org.joget.workflow.shark.WorkflowAssignmentManager - jwc_rushiharal7 : [processId=112_cotten_procrument_process1, processDefId=cotten_procrument#8#process1, participantId=ho, next user=[ho]]
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INFO 02 Aug 2020 16:46:59 org.joget.apps.app.lib.UserNotificationAuditTrail - jwc_rushiharal7 : Users to notify: [ho]
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INFO 02 Aug 2020 16:47:47 org.joget.apps.workflow.security.WorkflowAuthenticationProvider - jwc_rushiharal7 : Authentication for user ho (223.189.23.49) : true

This is today's log. There is no error or warning but pretty sure something have gone south here.

I need this plugin to be working Please help.

Have any of the users "ho, manisha, rushikesh, virat", used their mobile phone Chrome browser and surf to your joget site and accepted "allow notification" before?

There should be follow up message after

INFO 02 Aug 2020 16:46:59 org.joget.apps.app.lib.UserNotificationAuditTrail - jwc_rushiharal7 : Users to notify: [ho]

that says send email completed, or notification sent.

It is likely that these users have no emails configured, or didn't subscribe/allow push notification from their phone browser or added the joget site as PWA yet.