Pop up showing no network access in screen

[Sad123hana]

I am using sony Xperia c5 ultra mobile, since yesterday evening im continuously showing no network access pop up in my screen when using data network , when i am disable data then pop not apear. Plz help

[Uliwooly]

@Sad123hana 

redownload the APN settings > restart the phone > report back

settings > network  & internet > internet settings > accept