Sent docs for Adobe signature. no time stamp under signature when signed. Only 1 client

[Brayden Foote]

HI!

I send out some documents for signatures to my clients through Adobe signature, Enter their email, place the signature or initial box and send it out.  Most of the time it comes back with their signature and a small time stamp under the signature in blue writing. everyone has been signing on their phone. same process. but this one client doesn't have the time stamp under the signature. I'm using the certificate for the time stamp but getting a little pushback on that.  is there a known reason why there would not be a time stamp underneath the signature? type of email account they are using?