Fallback to schedule automation in UTC timezone if unset

- Handle null automation ids in calls to get_automation function

src/khoj/database/adapters/__init__.py

@@ -1794,7 +1794,7 @@ class AutomationAdapters:
     def get_automation(user: KhojUser, automation_id: str) -> Job:
         # Perform validation checks
         # Check if user is allowed to delete this automation id
-        if not automation_id.startswith(f"automation_{user.uuid}_"):
+        if not is_none_or_empty(automation_id) or automation_id.startswith(f"automation_{user.uuid}_"):
             raise ValueError("Invalid automation id")
         # Check if automation with this id exist
         automation: Job = state.scheduler.get_job(job_id=automation_id)

src/khoj/routers/helpers.py

@@ -1977,7 +1977,13 @@ def schedule_automation(
         # Run automation at some random minute (to distribute request load) instead of running every X minutes
         crontime = " ".join([str(math.floor(random() * 60))] + crontime.split(" ")[1:])
 
-    user_timezone = pytz.timezone(timezone)
+    # Convert timezone string to timezone object
+    try:
+        user_timezone = pytz.timezone(timezone)
+    except pytz.UnknownTimeZoneError:
+        logger.error(f"Invalid timezone: {timezone}. Fallback to use UTC to schedule automation.")
+        user_timezone = pytz.utc
+
     trigger = CronTrigger.from_crontab(crontime, user_timezone)
     trigger.jitter = 60
     # Generate id and metadata used by task scheduler and process locks for the task runs