Do you need cause of death certificate to close deceased account with your name on the account?

Yes. If a joint account held by multiple parties is to be closed, the bank would require the signature of both or all parties involved. In this case, since one of the account holders is deceased, their death certificate is required for the bank to know that they are dead and you are now the only holder of the account and you can close it without any issues after you show them the document.