Add the exception error message string to the message box output to know what went wrong:
MsgBox("Could not send email." + ex.Message)
Note also that you must allow less secure applications sending mail for the used Goggle mail account (see Allow or disallow less secure apps to access accounts - G Suite Administrator Help
]) as noted at Step 2 - Use the Gmail SMTP Server
at Send email from a printer, scanner, or app - G Suite Administrator Help
Other possible error sources are firewalls blocking the request.
And, as known meanwhile by getting the error message, the 'From' field does not contain a valid email address:
email.From = New MailAddress("Ordering system prototype")