diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php b/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php
index 71fe68ed2..133c6b57c 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php
@@ -165,16 +165,6 @@ abstract class Utils
 			|| !\preg_match('/[^\x09\x10\x13\x0A\x0D\x20-\x7E]/', $sValue);
 	}
 
-	private static function StrMailDomainToLower(string $sValue) : string
-	{
-		$aParts = \explode('@', $sValue);
-		if ($iLast) {
-			$iLast = \count($aParts) - 1;
-			$aParts[$iLast] = \mb_strtolower($aParts[$iLast]);
-		}
-		return \implode('@', $aParts);
-	}
-
 	public static function StripSpaces(string $sValue) : string
 	{
 		return static::Trim(
@@ -421,19 +411,14 @@ abstract class Utils
 
 	public static function GetAccountNameFromEmail(string $sEmail) : string
 	{
-		$sResult = '';
-		if (\strlen($sEmail)) {
-			$iPos = \strrpos($sEmail, '@');
-			$sResult = (false === $iPos) ? $sEmail : \substr($sEmail, 0, $iPos);
-		}
-
-		return $sResult;
+		$iPos = \strrpos($sEmail, '@');
+		return (false === $iPos) ? $sEmail : \substr($sEmail, 0, $iPos);
 	}
 
 	public static function GetDomainFromEmail(string $sEmail) : string
 	{
-		$aParts = \explode('@', $sEmail);
-		return isset($aParts[1]) ? \array_pop($aParts) : '';
+		$iPos = \strrpos($sEmail, '@');
+		return (false === $iPos) ? '' : \substr($sEmail, $iPos + 1);
 	}
 
 	public static function GetClearDomainName(string $sDomain) : string
@@ -693,17 +678,16 @@ abstract class Utils
 	/**
 	 * Converts xn--du8h.snappymail.eu to 📧.snappymail.eu
 	 */
-	public static function IdnToUtf8(string $sStr, bool $bLowerCase = false) : string
+	public static function IdnToUtf8(string $sStr) : string
 	{
-		if (\strlen($sStr) && \preg_match('/(^|\.|@)xn--/i', $sStr)) {
+		if (\preg_match('/(^|\.|@)xn--/i', $sStr)) {
 			try
 			{
 				$sStr = \SnappyMail\IDN::anyToUtf8($sStr);
 			}
 			catch (\Throwable $oException) {}
 		}
-
-		return $bLowerCase ? static::StrMailDomainToLower($sStr) : $sStr;
+		return $sStr;
 	}
 
 	/**
diff --git a/snappymail/v/0.0.0/app/libraries/RainLoop/Model/Domain.php b/snappymail/v/0.0.0/app/libraries/RainLoop/Model/Domain.php
index d40b7ca7d..77e2b6060 100644
--- a/snappymail/v/0.0.0/app/libraries/RainLoop/Model/Domain.php
+++ b/snappymail/v/0.0.0/app/libraries/RainLoop/Model/Domain.php
@@ -102,21 +102,26 @@ class Domain implements \JsonSerializable
 		$this->aliasName = \strtolower(\idn_to_ascii($sAliasName));
 	}
 
-	public function ValidateWhiteList(string $sEmail, string $sLogin = '') : bool
+	public function ValidateWhiteList(string $sEmail, string $sLogin) : bool
 	{
 		$sW = \trim($this->whiteList);
-		if (\strlen($sW))
-		{
-			$sEmail = \MailSo\Base\Utils::IdnToUtf8($sEmail, true);
-			$sLogin = \MailSo\Base\Utils::IdnToUtf8($sLogin, true);
-
-			$sW = \preg_replace('/([^\s]+)@[^\s]*/', '$1', $sW);
-			$sW = ' '.\trim(\preg_replace('/[\s;,\r\n\t]+/', ' ', $sW)).' ';
-
-			$sUserPart = \MailSo\Base\Utils::GetAccountNameFromEmail(\strlen($sLogin) ? $sLogin : $sEmail);
-			return false !== \stripos($sW, ' '.$sUserPart.' ');
+		if ($sW) {
+			$sEmail = \mb_strtolower($sEmail);
+			$sLogin = \mb_strtolower($sLogin);
+			$sUserPart = \MailSo\Base\Utils::GetAccountNameFromEmail($sLogin ?: $sEmail);
+			$sItem = \strtok($sW, " ;,\n");
+			while (false !== $sItem) {
+				$sItem = \mb_strtolower(\idn_to_ascii(\trim($sItem)));
+				if ($sItem && (
+					$sLogin === $sItem || $sEmail === $sItem
+					|| $sUserPart === $sItem || \str_starts_with($sItem, "{$sUserPart}@")
+				)) {
+					return true;
+				}
+				$sItem = \strtok(" ;,\n");
+			}
+			return false;
 		}
-
 		return true;
 	}