Problem with Zoho Sign Flow Signature Field

I created a flow in Zoho Flow that automatically generates and sends a contract from a Zoho CRM record when I change the deal stage to Paperwork.

However, the flow is only working for some records but not all of them. For some records, I am getting the following error message when checking the flow task history:

Configure a signature in your Zoho Sign profile
 and try again

You can see a screenshot here: https://cl.ly/e2f4e8cfb7b8

I have tried multiple strategies to fix it but nothing is working.

I have taken the contact name and email from an account record that works with this flow and used it in an account that returns the error message but I keep getting the error message.
I have taken the contact name and email from an account record that doesn't work with this flow and used it as the contact for a record that does work with the flow and the flow continues to work properly.
I rechecked the connections, accounts, Sign document, etc. multiple times.

In addition, I do not fully understand the error message. I already have a Zoho Sign profile signature setup for my account and the document that is part of this flow does not even require my signature.

The main question is why am I getting an error message asking me to configure a Zoho Sign profile signature when I already have one for my account?

If it is asking me to configure a signature for the client, that doesn't make sense because I obviously don't have their signature, that's why I'm sending the document to get their signature. And even if this is the case, why is it working for some accounts but not all of them.

Please advise. I've been struggling with this for two days and would like to solve this as soon as possible.