diff --git a/services/nginx/app/routes/authRoute.php b/services/nginx/app/routes/authRoute.php
index 562c7d34..60dcbd13 100644
--- a/services/nginx/app/routes/authRoute.php
+++ b/services/nginx/app/routes/authRoute.php
@@ -416,7 +416,7 @@ class authRoute
 
             if ($matchingEconomicCustomer !== null) {
                 if ($localUserExists) {
-                    $response->error('Company phone number already registered 01', 400);
+                    $response->error('Company phone number already registered', 400);
                 }
 
                 $this->bootstrapLocalCustomerOrFail($companyPhone);
@@ -441,12 +441,35 @@ class authRoute
             }
 
             if ($localUserExists) {
-                $response->error('Company phone number already registered 02', 400);
+                $response->error('Company phone number already registered', 400);
             }
 
             // Get the CVR company information used for the e-conomic customer payload.
-            $companyInformation = (new virkdata())->getCompanyInformation($cvr, '', []);
-            $name = (string)($companyInformation->name ?? '');
+            $companyInformation = null;
+            try {
+                $companyInformation = (new virkdata())->getCompanyInformation((string)$cvr, '', []);
+            } catch (Exception $exception) {
+                $this->logRegisterCvrIssue('AUTH_REGISTER_CVR_LOOKUP_FAILED', [
+                    'phase' => 'cvr_lookup',
+                    'cvr' => (string)$cvr,
+                    'requestedCustomerNumber' => $companyPhone,
+                    'message' => $exception->getMessage(),
+                ]);
+                $response->error('CVR could not be verified. Please check the CVR number and try again.', 400);
+                return;
+            }
+
+            $name = trim((string)($companyInformation->name ?? ''));
+            if ($name === '') {
+                $this->logRegisterCvrIssue('AUTH_REGISTER_CVR_LOOKUP_INVALID_RESPONSE', [
+                    'phase' => 'cvr_lookup',
+                    'cvr' => (string)$cvr,
+                    'requestedCustomerNumber' => $companyPhone,
+                ]);
+                $response->error('CVR could not be verified. Please check the CVR number and try again.', 400);
+                return;
+            }
+
             try {
                 $result = $economic->createCustomer(
                     (int)$companyPhone,
@@ -765,7 +788,7 @@ class authRoute
     private function localCustomerNumberExists(int $customerNumber): bool
     {
         $rows = (new users_o())->getFieldsWhere([
-            'customer_number' => (int)$customerNumber,
+            'customer_number' => (string)$customerNumber,
         ], ['id']);
 
         return count($rows) > 0;
diff --git a/services/nginx/app/tests/auth/RegisterCvrTest.php b/services/nginx/app/tests/auth/RegisterCvrTest.php
index e654effb..6b37250b 100644
--- a/services/nginx/app/tests/auth/RegisterCvrTest.php
+++ b/services/nginx/app/tests/auth/RegisterCvrTest.php
@@ -142,9 +142,14 @@ namespace classes {
         public static int $mock_zipcode = 2630;
         public static string $mock_city = 'Taastrup';
         public static string $mock_website = 'https://demo.test';
+        public static ?\RuntimeException $mock_exception = null;
 
         public function getCompanyInformation($cvr, $endpoint, $data): object
         {
+            if (self::$mock_exception !== null) {
+                throw self::$mock_exception;
+            }
+
             $result = new \stdClass();
             $result->name = self::$mock_name;
             $result->address = self::$mock_address;
@@ -419,6 +424,40 @@ namespace {
             'expected_error' => 'Parameter cvr must be at least 8 characters long',
             'expected_status' => 400,
         ],
+        [
+            'name' => 'CVR lookup failure returns validation error without creating customer',
+            'params' => array_merge($baseParams, ['cvr' => '11111112']),
+            'setup' => static function (): void {
+                \classes\virkdata::$mock_exception = new \RuntimeException('An error occurred');
+            },
+            'expected_error' => 'CVR could not be verified. Please check the CVR number and try again.',
+            'expected_status' => 400,
+            'assert' => static function (): void {
+                assert_true(count(\classes\economic::$create_calls) === 0, 'CVR lookup failures must not create e-conomic customers.');
+                assert_true(count(\classes\email::$sent) === 0, 'CVR lookup failures must not send welcome emails.');
+                assert_true(count(\classes\email::$superuser_notifications) === 0, 'CVR lookup failures must not send superuser notifications.');
+                assert_true(count(\classes\slack::$customer_registration_notifications) === 0, 'CVR lookup failures must not send Slack customer registration notifications.');
+                assert_true(count(\objects\logs_o::$entries) === 1, 'CVR lookup failures should be logged for diagnostics.');
+                assert_true(\objects\logs_o::$entries[0]['event'] === 'AUTH_REGISTER_CVR_LOOKUP_FAILED', 'CVR lookup failure should use the lookup failure log event.');
+            },
+        ],
+        [
+            'name' => 'CVR lookup without company name returns validation error without creating customer',
+            'params' => array_merge($baseParams, ['cvr' => '11111112']),
+            'setup' => static function (): void {
+                \classes\virkdata::$mock_name = '';
+            },
+            'expected_error' => 'CVR could not be verified. Please check the CVR number and try again.',
+            'expected_status' => 400,
+            'assert' => static function (): void {
+                assert_true(count(\classes\economic::$create_calls) === 0, 'CVR lookup responses without a company name must not create e-conomic customers.');
+                assert_true(count(\classes\email::$sent) === 0, 'CVR lookup responses without a company name must not send welcome emails.');
+                assert_true(count(\classes\email::$superuser_notifications) === 0, 'CVR lookup responses without a company name must not send superuser notifications.');
+                assert_true(count(\classes\slack::$customer_registration_notifications) === 0, 'CVR lookup responses without a company name must not send Slack customer registration notifications.');
+                assert_true(count(\objects\logs_o::$entries) === 1, 'CVR lookup responses without a company name should be logged for diagnostics.');
+                assert_true(\objects\logs_o::$entries[0]['event'] === 'AUTH_REGISTER_CVR_LOOKUP_INVALID_RESPONSE', 'CVR lookup response without a company name should use the invalid response log event.');
+            },
+        ],
         [
             'name' => 'Existing company phone with local customer stays blocked',
             'params' => $baseParams,
@@ -654,6 +693,7 @@ namespace {
         \classes\virkdata::$mock_zipcode = 2630;
         \classes\virkdata::$mock_city = 'Taastrup';
         \classes\virkdata::$mock_website = 'https://demo.test';
+        \classes\virkdata::$mock_exception = null;
         \objects\users_o::reset();
         \objects\logs_o::reset();