Using Odoo online 14. 

I'm receiving an error when trying to print an invoice from the PoS frontend. It says the order has been already synchronized and cannot be printed from frontend anymore but must be printed from the backend.

Did anyone have had this problem already? I've heard that with Odoo 15 (I'm using 14), it's possible to print from the frontend... but I don't want to upgrade version and ideally to solve the problem.

Could this be due to a network issue (we are wired to the modem)? Or could this be that tere is something wrong with the parameters of the synchro (frontend <> backend)?