I changed ec2 instance type from t2.medium to c5.xlarge and i can't useit

Question

I changed a ec2 instance type from t2.medium to c5.xlarge When restarted success. I can't connect it in private network.

ssh got error:Failed to connect to the host via ssh: ssh: connect to host ip-xx.internal port 22: Connection refused

before that, all is well

ena driver is enabled. but ethtool -i eth0 got vif

filename:       /lib/modules/4.9.0-7-amd64/kernel/drivers/net/ethernet/amazon/ena/ena.ko
version:        1.0.2
license:        GPL
description:    Elastic Network Adapter (ENA)
author:         Amazon.com, Inc. or its affiliates
srcversion:     73A3C8A8AA3F11D64B6D173
alias:          pci:v00001D0Fd0000EC21sv*sd*bc*sc*i*
alias:          pci:v00001D0Fd0000EC20sv*sd*bc*sc*i*
alias:          pci:v00001D0Fd00001EC2sv*sd*bc*sc*i*
alias:          pci:v00001D0Fd00000EC2sv*sd*bc*sc*i*
depends:
retpoline:      Y
intree:         Y
vermagic:       4.9.0-7-amd64 SMP mod_unload modversions
parm:           debug:Debug level (0=none,...,16=all) (int)

shell #sudo ethtool -i eth0
driver: vif
version:
firmware-version:
expansion-rom-version:
bus-info: vif-0
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: no

Answer 1

emmmmm

OS: debian stretch

install nvme driver sudo apt install nvme-cli

change/etc/fstabuseblkiddo not use /dev/xx

poweroff, change instance type and boot. success.