Make sure to check your users have joined, otherwise they won't be able to log in. You can check this and resend all sign up emails in bulk from the Members area.
Click into the Members area (icon with two heads at the top right of the page)
Click the funnel icon beside the search bar to toggle filter options
Deselect Include active and ensure only include added is ticked
Click the two tick icon to the right of the filter funnel to select all members
Click Add in the Actions panel on the right
Click Send/Resend Sign Up Email
Click Yes to confirm