In my sign up form for a website, I display a message belows the password field form.:
<em class="help-block">A minimum 8 characters password contains a combination of <strong>uppercase and lowercase letter</strong> and <strong>number</strong>.</em>
And if the participant still didn't match the password requirement, there'll be an error message:
A minimum 8 characters password contains a combination of uppercase and lowercase letter and number are required.
So far, there were 12 sign-up, but there were 2 participants failed and didn't understand this message, and complain about it.
FYI, this website's target audience were for international academics and professionals in chemistry, that's why the website is using English. I don't have any information where the participant who had this error were coming from.
Is there a more appropriate and clear error message that I can use in English?