Ok finally i found the solution.
Actually M2 return "Email has a wrong format" this error from following file
magento\module-sales\Model\Order\Address
And in this method there is a email validation
public function validate(Address $address)
{
$warnings = [];
foreach ($this->required as $code => $label) {
if (!$address->hasData($code)) {
$warnings[] = sprintf('%s is a required field', $label);
}
}
if (!filter_var($address->getEmail(), FILTER_VALIDATE_EMAIL)) {
$warnings[] = 'Email has a wrong format';
}
if (!filter_var(in_array($address->getAddressType(), [Address::TYPE_BILLING, Address::TYPE_SHIPPING]))) {
$warnings[] = 'Address type doesn\'t match required options';
}
return $warnings;
}
So i simply used the code from this method.
if (!filter_var("test@r-u-i-.com", FILTER_VALIDATE_EMAIL)) {
$warnings[] = 'Email has a wrong format';
}