First check both earbuds are turning on.
You can tell they are turned on if the LED on each earbud lights up or if you can hear "Power on" from each earbud when when they are removed from the case.
If either earbud is not turning on, make sure they are charged.
Check you can see the LED on each earbud lights up when the earbuds are placed in the case.
Check the charging plates on both buds and the charging pins in the case. Clean them with either an alcohol or anti-septic wipe, avoiding wipes that contain perfumes or soap.
If either or both earbuds are not charging or turning on please contact our support team via this link, they will be happy to help.
Next check that your StreamBuds SX are not connected to another Bluetooth device.
If they are, remove all entries for the StreamBuds SX in all Bluetooth menus on all devices in your home. Then try connecting to them again using this guide.
If your StreamBuds SX are still not working please contact our support team via this link, they will be happy to help.