diff --git a/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldInstanceTest.php b/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldInstanceTest.php
index df8ffad..653b647 100644
--- a/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldInstanceTest.php
+++ b/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldInstanceTest.php
@@ -195,16 +195,16 @@ public function testTextFieldInstances() {
     $errors = array_map(function($message) {return $message->message;}, $messages);
     $this->assertCount(8, $errors);
     sort($errors);
-    $message = 'Can\'t migrate source field field_text_long_plain_filtered configured with both plain text and filtered text processing.';
+    $message = 'Can\'t migrate source field field_text_long_plain_filtered configured with both plain text and filtered text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text';
     $this->assertEquals($errors[0], $message);
     $this->assertEquals($errors[1], $message);
-    $message = 'Can\'t migrate source field field_text_plain_filtered configured with both plain text and filtered text processing.';
+    $message = 'Can\'t migrate source field field_text_plain_filtered configured with both plain text and filtered text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text';
     $this->assertEquals($errors[2], $message);
     $this->assertEquals($errors[3], $message);
-    $message = 'Can\'t migrate source field field_text_sum_plain configured with both plain text processing and text_with_summary.';
+    $message = 'Can\'t migrate source field field_text_sum_plain of type text_with_summary configured with plain text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text';
     $this->assertEquals($errors[4], $message);
     $this->assertEquals($errors[5], $message);
-    $message = 'Can\'t migrate source field field_text_sum_plain_filtered configured with both plain text processing and text_with_summary.';
+    $message = 'Can\'t migrate source field field_text_sum_plain_filtered of type text_with_summary configured with plain text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text';
     $this->assertEquals($errors[6], $message);
     $this->assertEquals($errors[7], $message);
   }
diff --git a/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldTest.php b/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldTest.php
index 828755a..083af22 100644
--- a/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldTest.php
+++ b/core/modules/field/tests/src/Kernel/Migrate/d7/MigrateFieldTest.php
@@ -150,10 +150,10 @@ public function testTextFields() {
     $errors = array_map(function($message) {return $message->message;}, $messages);
     sort($errors);
     $this->assertCount(4, $errors);
-    $this->assertEquals($errors[0], 'Can\'t migrate source field field_text_long_plain_filtered configured with both plain text and filtered text processing.');
-    $this->assertEquals($errors[1], 'Can\'t migrate source field field_text_plain_filtered configured with both plain text and filtered text processing.');
-    $this->assertEquals($errors[2], 'Can\'t migrate source field field_text_sum_plain configured with both plain text processing and text_with_summary.');
-    $this->assertEquals($errors[3], 'Can\'t migrate source field field_text_sum_plain_filtered configured with both plain text processing and text_with_summary.');
+    $this->assertEquals($errors[0], 'Can\'t migrate source field field_text_long_plain_filtered configured with both plain text and filtered text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text');
+    $this->assertEquals($errors[1], 'Can\'t migrate source field field_text_plain_filtered configured with both plain text and filtered text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text');
+    $this->assertEquals($errors[2], 'Can\'t migrate source field field_text_sum_plain of type text_with_summary configured with plain text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text');
+    $this->assertEquals($errors[3], 'Can\'t migrate source field field_text_sum_plain_filtered of type text_with_summary configured with plain text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text');
   }
 
 }
diff --git a/core/modules/text/src/Plugin/migrate/field/d7/TextField.php b/core/modules/text/src/Plugin/migrate/field/d7/TextField.php
index 53e0938..c3d24c2 100644
--- a/core/modules/text/src/Plugin/migrate/field/d7/TextField.php
+++ b/core/modules/text/src/Plugin/migrate/field/d7/TextField.php
@@ -50,15 +50,15 @@ public function getFieldType(Row $row) {
       // If a text or text_long field has both plain text and filtered text
       // instances, skip the row.
       elseif ($plain_text && $filtered_text) {
-        $fieldName = $row->getSourceProperty('field_name');
-        throw new MigrateSkipRowException("Can't migrate source field $fieldName configured with both plain text and filtered text processing.");
+        $field_name = $row->getSourceProperty('field_name');
+        throw new MigrateSkipRowException("Can't migrate source field $field_name configured with both plain text and filtered text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text");
       }
     }
     elseif ($type == 'text_with_summary' && $plain_text) {
       // If a text_with_summary field has plain text instances, skip the row
       // since there's no such thing as a string_with_summary field.
-      $fieldName = $row->getSourceProperty('field_name');
-      throw new MigrateSkipRowException("Can't migrate source field $fieldName configured with both plain text processing and text_with_summary.");
+      $field_name = $row->getSourceProperty('field_name');
+      throw new MigrateSkipRowException("Can't migrate source field $field_name of type text_with_summary configured with plain text processing. See https://www.drupal.org/docs/8/upgrade/known-issues-when-upgrading-from-drupal-6-or-7-to-drupal-8#plain-text");
     }
 
     return $type;