Switched to LineMobile, now Line messages are sometimes delayed several minutes

[BadCash]

First of all, my phone is a Huawei GR5 2017 (Honor 6x) running Android 7.0.

 

I just switched from using a TrueMove H prepaid SIM-card to using a LineMobile SIM-card yesterday. Today I noticed that sometimes Line messages are delayed a few minutes, or don't arrive until I turn my display on. For example, I just received a message notification at 10.58pm, exactly the same time I turned on the display on the phone, but the message time in the chat says the message was sent (or arrived?) at 10.56pm.

 

I haven't touched any settings, and Line has been working fine without any delays for the past 5 months on this phone. It was notoriously hard to set up correctly at first because of Huawei's aggressive battery optimizations, but I have had Line, Messenger and other messaging apps working perfectly for 5 months, and I just noticed this today which tells me it might have something to do with the carrier.

 

The LineMobile app (the app for the SIM card, not Line Messenger) has a toggle for using unlimited free 256kbps data or limited 4G data, and I currently have it set to 256kbps. The funny thing is that Line messages are supposed to be free anyway, i.e. they don't use any of the limited full speed 4G quota.

 

LineMobile uses DTAC's network, my APN settings (which are the default settings) are

 

Name: dtac internet

APN: www.dtac.co.th

MMSC: http://m.dtacplay.com

MCC: 520

MNC: 05

APN type: default,supl

APN protocol: IPv4

APN roaming protocol: IPv4

Bearer: Unspecified

MVNO type: None

 

All others are "Not set".

 

Has anyone else experienced this? Could it be some setting that needs tweaking somewhere? Or could it be some type of limitation when using the unlimited 256kbps connection?

Edited November 16, 2017 by BadCash