Complaining about an invalid email address would be just fine - but yes, failing to spot the invalid input and display a meaningful message (rather than a 500 error) is a bug.

Of course, I'm not certain there is such a bug in this case. It could be a configuration error. Although this was a clean installation with no modifications. It might be worth others checking their stores to see if something similar occurs.

zyper - thanks for that, I'll give your suggestion a try! I'm glad to hear you found a resolution to your problem too!!

(BTW - I posted earlier as scarter2. I forgot I already had this account)