diff --git a/agenta-backend/agenta_backend/models/converters.py b/agenta-backend/agenta_backend/models/converters.py
index 429ad1589..72a0d174d 100644
--- a/agenta-backend/agenta_backend/models/converters.py
+++ b/agenta-backend/agenta_backend/models/converters.py
@@ -167,12 +167,17 @@ async def human_evaluation_db_to_pydantic(
         variant_name = (
             evaluation_variant.variant.variant_name
             if isinstance(evaluation_variant.variant_id, uuid.UUID)
-            else str(evaluation_variant.variant.variant_id)
+            else str(evaluation_variant.variant_id)
         )
         variants_names.append(str(variant_name))
-        variants_ids.append(str(evaluation_variant.variant.id))
-        revisions.append(str(evaluation_variant.variant_revision.revision))
-        variants_revision_ids.append(str(evaluation_variant.variant_revision.id))
+        variants_ids.append(str(evaluation_variant.variant_id))
+        variant_revision = (
+            str(evaluation_variant.variant_revision.revision)
+            if isinstance(evaluation_variant.variant_revision_id, uuid.UUID)
+            else " None"
+        )
+        revisions.append(variant_revision)
+        variants_revision_ids.append(str(evaluation_variant.variant_revision_id))
 
     return HumanEvaluation(
         id=str(evaluation_db.id),
diff --git a/agenta-backend/agenta_backend/routers/container_router.py b/agenta-backend/agenta_backend/routers/container_router.py
index fb678ff9a..ea47ecc08 100644
--- a/agenta-backend/agenta_backend/routers/container_router.py
+++ b/agenta-backend/agenta_backend/routers/container_router.py
@@ -1,3 +1,4 @@
+import uuid
 import logging
 
 from typing import List, Optional, Union
@@ -163,8 +164,20 @@ async def construct_app_container_url(
 
     if base_id:
         object_db = await db_manager.fetch_base_by_id(base_id)
-    elif variant_id:
+    elif variant_id and variant_id != "None":
+        # NOTE: Backward Compatibility
+        # ---------------------------
+        # When a user creates a human evaluation with a variant and later deletes the variant,
+        # the human evaluation page becomes inaccessible due to the backend raising a
+        # "'NoneType' object has no attribute 'variant_id'" error. To suppress this error,
+        # we will return the string "None" as the ID of the variant.
+        # This change ensures that users can still view their evaluations; however,
+        # they will no longer be able to access a deployment URL for the deleted variant.
+        # Therefore, we ensure that variant_id is not "None".
         object_db = await db_manager.fetch_app_variant_by_id(variant_id)
+    else:
+        # NOTE: required for backward compatibility
+        object_db = None
 
     # Check app access
     if isCloudEE():
diff --git a/agenta-backend/agenta_backend/services/db_manager.py b/agenta-backend/agenta_backend/services/db_manager.py
index c83eb7bdc..99080a13f 100644
--- a/agenta-backend/agenta_backend/services/db_manager.py
+++ b/agenta-backend/agenta_backend/services/db_manager.py
@@ -2737,24 +2737,50 @@ async def fetch_evaluations_by_resource(resource_type: str, resource_ids: List[s
 
     async with db_engine.get_session() as session:
         if resource_type == "variant":
-            query = select(EvaluationDB).filter(EvaluationDB.variant_id.in_(ids))
-        elif resource_type == "testset":
-            query = select(EvaluationDB).filter(EvaluationDB.testset_id.in_(ids))
-        elif resource_type == "evaluator_config":
+            result_evaluations = await session.execute(
+                select(EvaluationDB)
+                .filter(EvaluationDB.variant_id.in_(ids))
+                .options(load_only(EvaluationDB.id))  # type: ignore
+            )
+            result_human_evaluations = await session.execute(
+                select(HumanEvaluationDB)
+                .join(HumanEvaluationVariantDB)
+                .filter(HumanEvaluationVariantDB.variant_id.in_(ids))
+                .options(load_only(HumanEvaluationDB.id))  # type: ignore
+            )
+            res_evaluations = result_evaluations.scalars().all()
+            res_human_evaluations = result_human_evaluations.scalars().all()
+            return res_evaluations + res_human_evaluations
+
+        if resource_type == "testset":
+            result_evaluations = await session.execute(
+                select(EvaluationDB)
+                .filter(EvaluationDB.testset_id.in_(ids))
+                .options(load_only(EvaluationDB.id))  # type: ignore
+            )
+            result_human_evaluations = await session.execute(
+                select(HumanEvaluationDB)
+                .filter(HumanEvaluationDB.testset_id.in_(ids))
+                .options(load_only(HumanEvaluationDB.id))  # type: ignore
+            )
+            res_evaluations = result_evaluations.scalars().all()
+            res_human_evaluations = result_human_evaluations.scalars().all()
+            return res_evaluations + res_human_evaluations
+
+        if resource_type == "evaluator_config":
             query = (
                 select(EvaluationDB)
                 .join(EvaluationDB.evaluator_configs)
                 .filter(EvaluationEvaluatorConfigDB.evaluator_config_id.in_(ids))
             )
-        else:
-            raise HTTPException(
-                status_code=400,
-                detail=f"resource_type {resource_type} is not supported",
-            )
+            result = await session.execute(query)
+            res = result.scalars().all()
+            return res
 
-        result = await session.execute(query)
-        res = result.scalars().all()
-        return res
+        raise HTTPException(
+            status_code=400,
+            detail=f"resource_type {resource_type} is not supported",
+        )
 
 
 async def delete_evaluations(evaluation_ids: List[str]) -> None:
diff --git a/agenta-web/src/components/Playground/Views/ParametersView.tsx b/agenta-web/src/components/Playground/Views/ParametersView.tsx
index 08ad60b80..47d5278d2 100644
--- a/agenta-web/src/components/Playground/Views/ParametersView.tsx
+++ b/agenta-web/src/components/Playground/Views/ParametersView.tsx
@@ -11,6 +11,7 @@ import {usePostHogAg} from "@/hooks/usePostHogAg"
 import {isDemo} from "@/lib/helpers/utils"
 import {useQueryParam} from "@/hooks/useQuery"
 import {dynamicComponent, dynamicService} from "@/lib/helpers/dynamic"
+import {checkIfResourceValidForDeletion} from "@/lib/helpers/evaluate"
 
 const PromptVersioningDrawer: any = dynamicComponent(
     `PromptVersioningDrawer/PromptVersioningDrawer`,
@@ -131,14 +132,24 @@ const ParametersView: React.FC<Props> = ({
         })
     }
 
-    const handleDelete = () => {
-        deleteVariant(() => {
-            if (variant.persistent) {
-                return deleteSingleVariant(variant.variantId).then(() => {
-                    onStateChange(false)
-                })
-            }
-        })
+    const handleDelete = async () => {
+        try {
+            if (
+                !(await checkIfResourceValidForDeletion({
+                    resourceType: "variant",
+                    resourceIds: [variant.variantId],
+                }))
+            )
+                return
+
+            deleteVariant(() => {
+                if (variant.persistent) {
+                    return deleteSingleVariant(variant.variantId).then(() => {
+                        onStateChange(false)
+                    })
+                }
+            })
+        } catch {}
     }
 
     useEffect(() => {