If your projector image appears blurry, this can be a symptom of the projector being out of focus. Below is an example picture of how the picture looks with proper focus and out of focus.
To adjust the focus, please identify your projector model with the help of the pictures below, then consult the correct manual:
Optoma X605 / Optoma X605e
https://www.optoma.co.uk/ContentStorage/Documents/478ecd34-4acb-46be-9c19-0e3dd73bef1e.pdf
NEC PA903X
https://www.necdisplay.com/documents/UserManuals/PA653U.PA803U.PA863W.PA903X_UsserManual.pdf