Same here !
This just happened to us for the first time today. I would like to know how to disable this feature?!
Since the order is being sent by email, if they receive it, then the email is fine ; why need to verify it afterwards?
Plus I noticed it is capital sensitive ; a customer typed his email right but the first letter being a capital it didn’t let him proceed. Took me a while to udnerstand that.
Thanks for any info