diff --git a/apps/resm/migrations/0004_alter_paper_fail_reason.py b/apps/resm/migrations/0004_alter_paper_fail_reason.py
new file mode 100644
index 0000000..91f504b
--- /dev/null
+++ b/apps/resm/migrations/0004_alter_paper_fail_reason.py
@@ -0,0 +1,18 @@
+# Generated by Django 4.2.27 on 2026-01-28 08:26
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('resm', '0003_paper_o_keywords'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='paper',
+            name='fail_reason',
+            field=models.TextField(blank=True, null=True),
+        ),
+    ]
diff --git a/apps/resm/models.py b/apps/resm/models.py
index 49ceca2..cf9cd70 100644
--- a/apps/resm/models.py
+++ b/apps/resm/models.py
@@ -32,11 +32,7 @@ class Paper(BaseModel):
         default="meta_only",  # meta_only / abstract_ready / fulltext_ready / parsed / failed
         db_index=True
     )
-    fail_reason = models.CharField(
-        max_length=50,
-        null=True,
-        blank=True
-    )
+    fail_reason = models.TextField(null=True, blank=True)
 
     source = models.CharField(
         max_length=20,