You probably don’t need to restart OH. Going into the settings for the cloud in the GUI and saving is enough to restart the connector.
There are may threads on this you can read about this such as: Disconnected from the openHAB Cloud service - #110 by Josh_Schachat
and How to automatically restart cloud connector after an unexpected disconnection - #25 by ssalonen
and Openhab cloud connection stops working, does not try to reconnect - #63 by momo90