why am i getting an alert on the top of JIRA?

[Kh_Ehsana_Rahman]

hi, 
i renewed my license yesterday. why Im seeing this msg constantly on the top of my JIRA ? I have attached the screenshot. Please have a look. 
Also Im not able to work properly in "permission schemes".

Please help me. 
Thank you

[Luther Hargrove]

The only way tha tI would imagine that you could accomplish this is with javascript. You would have to do some javascript to pull in the assignee field and then if it is modified to then force another field to be required. It would have to be pretty complex though as to not make it required if it is then assigned again to another person.

JIRA Service Desk might be a good item for you to research as it may have some additional options for you to use.