Why internet can only be accessed with H+ mode but not with 4G LTE mode on my US Samsung devices?

[Android Central Question]

I am currently visiting Bangladesh ( a south east asian country) from USA . I have 3 Samsung devices (Galaxy S8 Galaxy S7 edge and galaxy tab 3) and none of them are working with 4G LTE. Now ,its not like the problem started as soon as I landed here . All of them were working fine with local 4G SIM for 1 month but after that the internet can only be used if the 3G only mode is selected . If the 4G network mode is selected , the network successfully connects but I get a "404 not found " message if I try to use the browser . Only apps that run are Facebook and whatspp , but occasionally , they too give trouble on 4G.
However , If I turn the samsung device into a hotspot using the same 4G network settings , I can use the internet flawlessly on my laptop or any other android devices .
I have tried the following :
- I talked with the carrier customer support and got the correct APN settings
-I have cleaned cache memory and other memories of the affected apps like chrome browser.
-I have tried using a different DNS server, like google dns or 1dot1dot1dot1
-I have a mobile hotspot device (pocket wifi) . I used the same 4G sim in it and tried connecting my Samsung devices to the wifi network generated by the hotspot device. The samsung devices only work when I change the setting of the hotspot device to 3G only mode.
None of the above measures solved the problem and no one can seem to come up with a solution , not even the customer service . I know the problem I am facing is quite bizarre as its only affecting my samsung devices , my oppo devices are working just fine . Please Help
Kind Regards
K. Nandy

 

[mustang7757]

Try resetting network in settings?

I'll leave a Link to register so you can communicate here as a guest account you can only post questions but can't reply.https://forums.androidcentral.com/showthread.php?t=409154