Huawei Ascend P6 — Huawei Ascend p6 facing ussues for recieving messages from whatsappa and viber

HI,

i have Huawei ascend p6 and am facing some problem with all the messaging apps like whatspp, viber, talkray, when some one send any message am receiving it after 30-40 minutes if the phone is on sleep mode. The message will be delivered when i open the application, i have changed the power settings from endurance to normal and kept the settings for all messaging apps keep running on background. Some one please help me to fix this issue.

Thanks
Shams