Couldn't update verification problem

[Kishorekethineni]

I'm using Nokia 3. I got oreo update. But while I'm trying to update it showing that "couldn't install verification problem" after completion of download. How can I resolve this.

 

[Rukbat]

Has the phone ever been rooted? If it has, it can't update (and shouldn't - updating a rooted phone could brick it).

If not, you'll probably have to back everything up (see Backing up an Android Device), then flash the new ROM, then restore everything.