diff --git a/td/telegram/ContactsManager.cpp b/td/telegram/ContactsManager.cpp
index b9b28c913..990e5369c 100644
--- a/td/telegram/ContactsManager.cpp
+++ b/td/telegram/ContactsManager.cpp
@@ -127,7 +127,7 @@ class SetAccountTtlQuery : public Td::ResultHandler {
 
     bool result = result_ptr.move_as_ok();
     if (!result) {
-      return on_error(id, Status::Error(500, "Internal Server Error"));
+      return on_error(id, Status::Error(500, "Internal Server Error: failed to set account TTL"));
     }
 
     promise_.set_value(Unit());
@@ -2151,7 +2151,7 @@ class ImportChatInviteQuery : public Td::ResultHandler {
     auto dialog_ids = UpdatesManager::get_chat_dialog_ids(ptr.get());
     if (dialog_ids.size() != 1u) {
       LOG(ERROR) << "Receive wrong result for ImportChatInviteQuery: " << to_string(ptr);
-      return on_error(id, Status::Error(500, "Internal Server Error"));
+      return on_error(id, Status::Error(500, "Internal Server Error: failed to join chat by invite link"));
     }
     auto dialog_id = dialog_ids[0];
 
diff --git a/td/telegram/StickersManager.cpp b/td/telegram/StickersManager.cpp
index fd69b1628..7909b1f65 100644
--- a/td/telegram/StickersManager.cpp
+++ b/td/telegram/StickersManager.cpp
@@ -2681,7 +2681,7 @@ StickerSetId StickersManager::on_get_messages_sticker_set(StickerSetId sticker_s
   }
   if (sticker_set_id.is_valid() && sticker_set_id != set_id) {
     LOG(ERROR) << "Expected " << sticker_set_id << ", but receive " << set_id << " from " << source;
-    on_load_sticker_set_fail(sticker_set_id, Status::Error(500, "Internal Server Error"));
+    on_load_sticker_set_fail(sticker_set_id, Status::Error(500, "Internal Server Error: wrong sticker set received"));
     return StickerSetId();
   }
 
diff --git a/td/telegram/files/FileUploader.cpp b/td/telegram/files/FileUploader.cpp
index 72860950e..5ad06ac57 100644
--- a/td/telegram/files/FileUploader.cpp
+++ b/td/telegram/files/FileUploader.cpp
@@ -302,7 +302,7 @@ Result<size_t> FileUploader::process_part(Part part, NetQueryPtr net_query) {
   }
   if (!result.ok()) {
     // TODO: it is possible
-    return Status::Error(500, "Internal Server Error");
+    return Status::Error(500, "Internal Server Error during file upload");
   }
   return part.size;
 }