booting problem on trying to expand the partition size of linux

[Ashish]

Booting error

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.18.0-15-generic 4.18.0-15.16~18.04.1
ProcVersionSignature: Ubuntu 4.18.0-15.16~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CasperVersion: 1.394
CurrentDesktop: ubuntu:GNOME
Date: Sat Feb 23 11:55:43 2019
LiveMediaBuild: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install)