Editing activity notification mail


How can I edit this template? I tried that

print_unescaped($l->t('You are receiving this email because the following things happened at %s', array($_['https://myprove.com'])));

But I got this error

Error sharing Can't send mail with public link to https://myprove.com/index.php/s/uoRadasdasd8: Address in mailbox given [https://myprove.com/index.php/s/uoRoRZxsadasd8@] does not comply with RFC 2822, 3.6.2.

How can I do it?

Thank you so much