I used to sign with SMS code and Password, where did this go?

Signing in DocuSign with only SMS and your personal password is from 2025 no longer supported. You have two better alternatives.

Signing in DocuSign reselling products was in past possible with a personal password and an one-time SMS code you received on your mobile number at each electronic signature. This option was removed beginning 2025 and on the latest product update with DocuSign.

As alternative you can register a new authentication mean by registering either a passkey or by sign-up a Mobile-ID for you mobile number. On either options you will have to conduct a self-identification again, for which you require your mobile phone and your passport or national ID.

Hint: The best experience is registering a passkey and identify yourself with your passport.

For the MobileID path you can find further hints here: 
MobileID Activation on the fly with a Swiss number