Does this happen everywhere or in one particular place @Bigbros
This could be network mast congestion or mast issues. Your network will be able to help.
As a process of elimination can you try your sim card in another phone and then see what happens ?
Current Phone ~
Samsung Note 20 Ultra 5G SM-9820 _256Gb SnapDragon 865+
Samsung One Ui 2.5/ Android 10.