Hey Aliraza074,
We'd be happy to help out if you're having trouble upgrading your iCloud storage. Upgrading to latest software shouldn't have any impact on your ability to do so and the most likely reason for the issues is a networking issue.
We notice there's no cellular service on this device and could be contributing to the error received, but since connected to Wi-Fi, it'd be best to start by troubleshooting that. Go ahead and restart your modem/router and attempt the upgrade again, as this should refresh your home Wi-Fi network and help get it working as it should.
If you continue to have issues and receive this error, try moving to a location with cellular service or try connecting to another known-good Wi-Fi network.
For more help upgrading your iCloud storage, check out these steps:
How to upgrade on your iPhone, iPad, or iPod touch
1. Go to Settings, then tap your name.
2. Tap iCloud, then tap Manage Account Storage or Manage Storage. Or scroll down and tap Upgrade to iCloud+.
3. Tap Buy More Storage or Change Storage Plan.
4. Choose a plan and follow the onscreen instructions.
This is outlined in more detail here: Upgrade to iCloud+ - Apple Support
We hope this helps out.
Take care!