Not able to see Logs under Jobs in UiPath Orchestrator

Not able to see logs for any jobs. No error in Orchestrator UI.

There can be 2 possible reasons for this issue :
1. Robot role does not have permissions to create logs : 
- Log in to Orchestrator and click on Users tab.
- Click on Roles Page. 
- Edit permissions for role "Robot". 
and make sure for "Logs" Create checkbox is checked.      

2. Targets not defined properly in web.config file. 
n 2018.4 and later version if the targets do not have the proper syntax then the logs will not flow to any of the targets. In such scenario we have to validate and ensure that the syntax is right. 

Special Scenario :- In this case the NLog logging was turned on but the log path was not defined. Please refer the below screenshot to understand what should be the correct and incorrect scenario. 

Wrong Scenario :- Logging turned on , but path not defined. 

Correct Scenario:- Logging off

Correct Scenario:- Logging turned on and path defined. 

Also, please check Nlog target rules. You can refer to Logging Configuration for more insight.