Alcatel linkzone

Most of the time this problem comes up when someone is trying to use a prepaid phone SIM card in a non phone device.

Did you purchase a data connect plan and SIM card?  or did you just purchase a phone plan thinking that it would work in a data-only device?

While I'm waiting for an answer I will look up the hotspot you have asked about to see whether it is functional on AT&T network

That device was sold by T-Mobile/Sprint/Metro.

There were several different Generations sold, all the way back to 2 and 3-g only.

    There is a 2G only generation sold on Amazon as an unlocked device which will not work 2G is already shut down. 

     Look for model number to determine specs. 

It has to be unlocked to work on AT&T (on a correct data only plan).  

You would have to contact T-Mobile or which ever carrier its branded by to find out if it's locked.

I'm editing this... I just checked the Amazon listing and it says 4G. Hmmm... but I am using a sim card and a prepaid plan, but purchased the data only one. 

4G is good.  
what data plan?   

Is there a difference in the sin cards? Do I need a different sim card just for data only plans?

It is the 3gb for $25 plan.

The plan is correct for a hotspot.
 Yes, you need to have purchased a SIM card provisioned for data only.