BusinessConnect throw a "Failed to verify MIME Message. . . . Document Security-Verification Certificate not set in the Business Agreement" error even though the correct certificate is set.  The error message looks like this:

Error Message:
2023 Dec 19 12:01:18:382 GMT -0500 BW.BusinessConnect-OutBatch-05 Error [bw.logger] BW-EXT-LOG-100000 Job-347038976.347038976.9643CFFD-AEB4-4AEA-9C63-79334ADDFF4E.svl-tibbc-p23-OutBatch-05 Failed to verify signed S/MIME message. Please check Document Security-Verification Certificate setting in the Business Agreement. Failed to verify S/MIME message. Document Security-Verification Certificate not set in the Business Agreement. Failed to verify S/MIME message. Document Security-Verification Certificate not set in the Business Agreement.
    at com.tibco.ax.fw.ediint.ErrorObject.createException(ErrorObject.java:65)
 

BusinessConnect throw a "Failed to verify MIME Message. . . . Document Security-Verification Certificate not set in the Business Agreement" error even though the correct certificate is set.

all platforms

Check the BusinessConnect Certificate Store to see if an expired CA certificate that is used by the trading partner certificate is installed along with the current valid CA certificate.  The exception occurs because BC tries to verify the certificate chain, and errors out when it finds the expired CA certificate before it finds the current, valid one.  Removing the expired certificate will resolve the issue.