BibTeX does not have the right entry for preprints. This is a hack for producing the correct reference:
@booklet{EasyChair:7259,
author = {Kudumula Saikrishna Goud and Shakti P Jena},
title = {Modeling and Analysis of Vibrating Fixtures},
howpublished = {EasyChair Preprint 7259},
year = {EasyChair, 2021}}