Error in R: Error: LaTeX failed to compile HW6.tex. See https://yihui.org/tinytex/r/#debugging for debugging tips. See HW6.log for more info

Question

I meet following error message

This is pdfTeX, Version 3.141592653-2.6-1.40.24 (TeX Live 2022) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode

I was unable to find any missing LaTeX packages from the error log HW6.log.
! Missing endcsname inserted.
<to be read again> 
                   &
l.1006 .../figure-latex/forward \& backward-1.pdf}

Error: LaTeX failed to compile HW6.tex. See https://yihui.org/tinytex/r/#debugging for debugging tips. See HW6.log for more info.
Execution halted

I've looked for solution on https://yihui.org/issue/, but all steps didn't work