Sara R411 stop working

Hi all,
I bought a SARA R411 board, I flashed the proposed passthrough example but the result of every AT command was ERROR.
Moreover, after other attempts the module simply stopped to answer. What do you think is happened?

Dear @lorenzo.arena,

We have an R410, R412 and N211 as used SARA modules.
Which one do you have?

Can you check if your module has the latest firmware?

Can you give a list of AT commands you used and returned ERROR?

Best regards,