Stren or Strein: How To spell?

The word Stren is misspelled against Strein, a verb meaning "To strain."

Word contains consecutive vowels 'EI' in between alphabets str & n is misspelled as 'E' as letter 'I' is phonetically ignored
Wrong Spelling:  str-e-n 
Correct Spelling:  str-ei-n 
Explore spell check of Strein to spell without errors.