4G network issue

[Achie1]

My name 4G network has become very slow after December security update. When I removed my sim card and put in another smartphone, everything is fine. When I use other sim card, the problem comes back. Only 4G faces this issue. 3G is fine.

Galaxy A7 2017

[a72017niy]

https://r2.community.samsung.com/t5/Galaxy-A/Galaxy-A7-2017-slow-4g-after-security-update-SOLVED/td-...