TeX4ht shows error "v'^\dagger_i " while using align environment but not in inline equation

TeX4ht shows error "v'^\dagger_i " while using align environment but not in inline equation.

The pdflatex not shown error both inline and align environment

The Tex4ht error as follow: ! Double superscript. \s:p

l.6 \end{align}

TeX4ht needs proper grouping for subscripts and superscripts, especially in the MathML mode. So when you use multiple tokens, like v' as a part of your expression, you need to add braces:
\documentclass{article}
${v'}^{\dagger}_{i}$