my ipad show that your ipad could not be activated because the activation server is temporarily unavailable. And i try to connect it many times. but its not work . how should i do.

Check this link...

If you can't activate your iPhone - Apple Support

We are seeing regular reports of issues activating 9 year old iPad2 devices. If restart of your home router - or changing your DNS Server settings do not resolve the issue, you may need to seek assistance directly from Apple Support.

To restart you home router, disconnect power - then wait at least 30 seconds before restarting. When you router has rebooted (which may take several minutes), force-restart your iPad:

• On an iPad with a Home button: Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
• On an iPad with Face ID: Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the top button. When the Apple logo appears, release the button.

For recommended DNS servers (configured at your home router and/or your iPad), you might choose one of the following Recursive DNS Providers (IPv4 and IPv6 addresses included below):

Quad9

9.9.9.9

149.112.112.112

2620:fe::fe

2620:fe::9

OpenDNS

208.67.222.222

208.67.220.220

2620:0:ccc::2

2620:0:ccd::2

Cloudflare+APNIC

1.1.1.1

1.0.0.1

2606:4700:4700::1111

2606:4700:4700::1001

Should it be necessary to escalate your issue to Apple Support, the quickest route to engaging with Apple Support will be via the Contact Support link at top-right of this page.

You also need to be aware that very old first generation iPad2 can only be updated to iOS 9.3.5 (WiFi Only models) or iOS 9.3.6 (WiFi & Cellular models).

Apple ended update support for iPad2 in September 2016. Your iPad cannot be updated to iOS 10 or later major versions of iOS as the internal hardware does not meet the minimum technical requirements for new versions of iOS/iPadOS. This limitation cannot be bypassed - in addition to which, iPad2 is a 32-bit architecture device, whilst all recent versions of iOS/iPadOS are designed for 64-bit hardware platforms. iPad2 is effectively obsolete.

Compatible Apps for your iPad are increasingly difficult to find - as third-party developers are increasingly dropping support for older versions of iOS preceding iOS11/12/13. As older versions of Apps are removed from the Apple App Store, you’ll not be able to (re)download or install them - which may severely limit the usefulness and utility of your iPad if you should you ever, as now, need reset or restore your iPad. As such, if you want or need to access most current Apps, requiring more recent versions of iOS, you’ll need to consider replacement of your iPad with a newer or current model.

Of current models, even the entry-level iPad8 has specifications and capabilities that will massively outperform you current iPad - and is compatible with the vast majority of current Apps. Other models are more powerful still.

I hope this information provides helpful and succinct clarity as to your available options - and the limitations of your current iPad.