R11e-LTE-US Frequency Lock

I am trying to lock my SXT LTE US to EARFCN 2100. Sometime it switches to 500, causing my internet to run very slow. Here is the code I’m using to try this:

/interface lte  at-chat lte1 input=AT*Cell1,3,,2100,,

However, all I get back is:

output: ERROR

Am I doing this right?
Thank you!

Bump. Any help would be appreciated.

Unfortunately this is not supported on US modems

Thank you for getting back with me!