Activation lock

OK......try the steps in this link: If you can't activate your iPhone - Apple Support

If this doesn't help, use the Contact Support button at the top of this page, or visit your Apple Store Genius Bar.

https://support.apple.com/en-us/HT201441

Are you sure it's Activation Locked? The screen for that looks like this - I've indicated where you enter the ID and password:

Or does it look something like this? -

That's not Activation Lock but is asking for a four or six digit number you created to lock the device.

If either of those is not what you're seeing, what are you seeing? A photo might help (but don't include your ID).

If you schedule an appointment at your closest Apple Store Genius Bar, support is absolutely free. You just need to make an appointment and it won't cost you anything.

Since there's some confusion in what is going on, maybe it would be best if you called Apple directly: 1-800-MY-APPLE (this is the number in the US). If you are in another country, please identify.

They are two different devices so your phone working has little to do with your iPad. When you get the message the Activation Server can't be reached, it indicates you have a cellular iPad (I assume you do, yes?) and you need to determine why by either following the suggestions in the link I provided or seek help directly from Apple.

Did you purchase a used iPad?