According to § 312i Para. 1 S. 1 No. 1 BGB in conjunction with. Art. 246c No. 3 EGBGB, the customer must be provided with adequate, effective and accessible technical means and informed about how input errors can be recognised and corrected before the order is placed. Adequate technical means in this sense are clearly labelled

In the present case, the e-mail address is not shown on the order page/checkout.

This must be supplemented with appropriate correction options so that the consumer can recognise and correct incorrect entries.