Why does my machine shut off part way through steaming

My Starbucks barista will run beautifully for anout 2 minutes then slowly shut down. What needs to be replaced?

crwdns2893858:0crwdne2893858:0 crwdns2893862:0crwdne2893862:0

crwdns2894050:0crwdne2894050:0

crwdns2889612:0crwdne2889612:0 0
crwdns2892346:0crwdne2892346:0