diff --git a/api/src/chat/repositories/block.repository.ts b/api/src/chat/repositories/block.repository.ts
index c796e75..4ddb9aa 100644
--- a/api/src/chat/repositories/block.repository.ts
+++ b/api/src/chat/repositories/block.repository.ts
@@ -53,6 +53,7 @@ export class BlockRepository extends BaseRepository<
     if (
       block.message &&
       'attachment' in block.message &&
+      block.message.attachment.payload &&
       'url' in block.message.attachment.payload
     ) {
       this.logger.error(
diff --git a/api/src/chat/services/block.service.ts b/api/src/chat/services/block.service.ts
index f7353b7..f3fb45f 100644
--- a/api/src/chat/services/block.service.ts
+++ b/api/src/chat/services/block.service.ts
@@ -409,6 +409,7 @@ export class BlockService extends BaseService<Block, BlockPopulate, BlockFull> {
     if (
       block.message &&
       'attachment' in block.message &&
+      block.message.attachment.payload &&
       'url' in block.message.attachment.payload
     ) {
       this.logger.error(
diff --git a/api/src/chat/validation-rules/is-message.ts b/api/src/chat/validation-rules/is-message.ts
index 0b11cc8..fbd1589 100644
--- a/api/src/chat/validation-rules/is-message.ts
+++ b/api/src/chat/validation-rules/is-message.ts
@@ -71,7 +71,7 @@ export function isValidMessage(msg: any) {
             .required(),
           payload: Joi.object().keys({
             url: Joi.string().uri(),
-            attachment_id: Joi.string(),
+            attachment_id: Joi.string().allow(null),
           }),
         }),
         elements: Joi.boolean(),