Hello @Nur Hossain ,
Welcome to Q&A Forum!
Please follow the steps:
1.Firstly, please make sure there is enough free disk space for your Search server which hosts Query component.
2.Please go to SharePoint 2016 Central Administration >> Manage service applications >> Search service application, check if the search application topology is running well like:
3.Go to Application Management >> Manage services on server, make sure all search services are started:
4.Also, please try to restart "Search Host Controller Service" and "Search Query and Site Settings Service". After that, test again.
Thanks,
Echo Du
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