How to sign in Adobe sig

Hello, I am new to Adobe Sign, I just created some forms that need to be signed by several folks.  I sent them in the order they need to be signed, but running into issues when they try to sign the form.  Once they sign, 1) it does not allow them to submit so it can go to next person; and 2) they no longer are able to see their signature on the form.  can you guide me as to how I can help them with these issues.   thank you