diff --git a/odex25_mobile/odex_mobile/controllers/rest_api_v2/attendance.py b/odex25_mobile/odex_mobile/controllers/rest_api_v2/attendance.py
index f4bac7e9c..28581af93 100644
--- a/odex25_mobile/odex_mobile/controllers/rest_api_v2/attendance.py
+++ b/odex25_mobile/odex_mobile/controllers/rest_api_v2/attendance.py
@@ -190,16 +190,25 @@ class AttendanceController(http.Controller):
         if not employee:
             return http_helper.response(code=400, message=_("You are not allowed to perform this operation. please check with one of your team admins"), success=False)
         if body.get('action') and body.get('action') == 'sign_in':
-            timezone = user.tz or 'GMT'
+            timezone = user.tz or 'UTC'
             local_tz = pytz.timezone(timezone)
             now_gmt = datetime.now(local_tz)
             current_time_float = now_gmt.hour + now_gmt.minute / 60.0
             calendar = employee.resource_calendar_id
             before_work = getattr(calendar, 'grace_hour_before_work', 8.0)
             after_work = getattr(calendar, 'grace_hour_after_work', 16.0)
-            if before_work and after_work:
-                if current_time_float < before_work or current_time_float > after_work:
-                    return http_helper.response(code=400, message=_("Dear employee, your working hours have not started yet."), success=False)
+            if before_work > 0.0 and current_time_float < before_work:
+                return http_helper.response(
+                    code=400,
+                    message=_("Dear employee, your working hours have not started yet."),
+                    success=False
+                )
+            if after_work > 0.0 and current_time_float > after_work:
+                return http_helper.response(
+                    code=400,
+                    message=_("Dear employee, your working hours have ended."),
+                    success=False
+                )
         if employee.device_id != body.get('device_id'):
             return http_helper.errcode(code=403, message=_("Device id not matching with already exist in system please contact system admin"))
         try:
diff --git a/odex25_mobile/odex_mobile/models/resource.py b/odex25_mobile/odex_mobile/models/resource.py
index 35d081843..b86036b96 100644
--- a/odex25_mobile/odex_mobile/models/resource.py
+++ b/odex25_mobile/odex_mobile/models/resource.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
-from odoo import fields, models
+from odoo import fields, models, api, _
+from odoo.exceptions import ValidationError
 
 
 class ResourceCalendar(models.Model):
@@ -8,3 +9,20 @@ class ResourceCalendar(models.Model):
 
     grace_hour_before_work = fields.Float(string="Grace Hours Before Work")
     grace_hour_after_work = fields.Float(string="Grace Hours After Work")
+
+    @api.constrains('grace_hour_before_work', 'grace_hour_after_work')
+    def grace_hour_constrains(self):
+        for rec in self:
+            if hasattr(rec, 'is_full_day') and hasattr(rec, 'noke'):
+                if rec.is_full_day and not rec.noke:
+                    if rec.grace_hour_before_work and rec.full_min_sign_in:
+                        if rec.grace_hour_before_work > rec.full_min_sign_in:
+                            raise ValidationError(_(
+                                "Grace hours before work must be less than or equal to minimum sign-in time."
+                            ))
+
+                    if rec.grace_hour_after_work and rec.full_max_sign_out:
+                        if rec.grace_hour_after_work < rec.full_max_sign_out:
+                            raise ValidationError(_(
+                                "Grace hours after work must be **greater** than or equal to maximum sign-out time."
+                            ))
diff --git a/odex25_mobile/odex_mobile/validator.py b/odex25_mobile/odex_mobile/validator.py
index 7c4c65e9a..145566da4 100644
--- a/odex25_mobile/odex_mobile/validator.py
+++ b/odex25_mobile/odex_mobile/validator.py
@@ -38,25 +38,26 @@ class Validator:
         else:
             return page
 
-    def get_attendance_check(self,employee):
+    def get_attendance_check(self, employee):
         if not employee:
             return 'sign_out'
-        user = employee.user_id
-        timezone = user.tz or 'GMT'
-        local_tz = pytz.timezone(timezone)
-        now_gmt = datetime.datetime.now(local_tz)
-        current_time_float = now_gmt.hour + now_gmt.minute / 60.0
-
+        timezone = employee.user_id.tz or 'UTC'
+        now = datetime.datetime.now(pytz.timezone(timezone))
+        current_time = now.hour + now.minute / 60.0
         calendar = employee.resource_calendar_id
-        before_work = getattr(calendar, 'grace_hour_before_work', 8.0)
-        after_work = getattr(calendar, 'grace_hour_after_work', 16.0)
 
-        if before_work and after_work:
-            if current_time_float < before_work or current_time_float > after_work:
-                return 'sign_out'
+        if calendar:
+            if calendar.grace_hour_before_work > 0.0:
+                if current_time < calendar.grace_hour_before_work:
+                    return 'sign_out'
 
-        last = http.request.env['attendance.attendance'].sudo().search([('employee_id', '=', employee.id), ], order='name desc',
-                                                       limit=1)
+            if calendar.grace_hour_after_work > 0.0:
+                if current_time > calendar.grace_hour_after_work:
+                    return 'sign_out'
+
+        last = http.request.env['attendance.attendance'].sudo().search([('employee_id', '=', employee.id), ],
+                                                                       order='name desc',
+                                                                       limit=1)
         if last:
             return last.action
         else: