This will not cause an issue, I request you to provide me the below details which will help me to assist you better.
1. Go to Admin --> Requesters and select the requester for whom servicedesk was showing an error while creating request, send me the screenshot of the detail view such as below for analysis.
2. Similarly go to Admin --> Technicians and select the technician with whose login you got the error and edit his account, send me the screenshot of the sites and groups associated to him for analysis.
Regards
Charles
Servicedesk Plus
SDP Support - FAQ
ServiceDesk Plus - Help Desk Software of your Choice