Twilio "Send SMS" not allowing editing - Definition contains invalid parameters

[RThorek]

I have a couple of flows that use Twilio SMS, when trying to edit them I get the error:  "Definition contains invalid parameters."

I have tried replicating the flow from scratch which works on the first save (even making a simple two step flow), but then editing that saved flow throws the same error. Seems that editing the existing flow is the issue. Any ideas?

[RThorek · Accepted solution]

nevermind! 

Worked out that in advanced options there is a toggle (new?) icon next to the media option which seems to have changed its defaut. Toggling it back allows you to save without adding anything into the field.