SSL/TLS issue with FTP

Our hosted FTP server must have updated the certificate over the weekend. We are not unable to connect using
FTP RMTSYS(myftpserver) SECCNN(*SSL)

The error is
234 AUTH TLS successful
The server's certificate is not signed by a trusted certificate authority.
Do you want to trust the server's certificate temporarily in this session? (y/n)
Secure connection error, return code 6000

Connecting from a PC works just fine. The CA is "Let's Encrypt".

In DCM, I've populated all of the Let's Encrypt CA's along with ISRG Root 1 and 2.

What am I missing?
[Logo]<https://www.totalbizfulfillment.com/> Greg Wilburn
Director of IT
301.895.3792 ext. 1231
301.895.3895 direct
gwilburn@xxxxxxxxxxxxxxxxxxxxxxx<mailto:gwilburn@xxxxxxxxxxxxxxxxxxxxxxx>
1 Corporate Dr
Grantsville, MD 21536
www.totalbizfulfillment.com<http://www.totalbizfulfillment.com>