Verification of digital signature of inbound AS2 message failed Verification failed

Hi, I am a beginner int this field.

Trying a brodcast with a sap partner when he send me a message i receive this error:

Where am I wrong ?

Thank you very much.

Transaction log:
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] Inbound transmission is a AS2 message [XXXXXXXX-YYYYYYYYY], raw message size: 3.16 KB.
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] Inbound AS2 message is encrypted.
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] The inbound AS2 message data has been decrypted using the key "YYY", the encryption algorithm was "3DES", the key encryption algorithm was "RSA".
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] Inbound AS2 message is signed.
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] The sender used the algorithm "SHA-256" to sign the inbound AS2 message.
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] Using certificate "YYY" to verify inbound AS2 message signature.
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] Verification of digital signature of inbound AS2 message failed Verification failed

Verification certificate information:
Serial number (DEC): 99999999999999999999999999999999
Serial number (HEX): 00000000000000000000000000000000 Finger print (SHA-1): XX:XX:XX:XX:XX:XX:XX:XX:XX
Valid from: 5/31/22
Valid to: 5/31/23
Issuer: CN=Certum Domain Validation CA SHA2, OU=Certum Certification Authority, O=Unizeto Technologies S.A., C=PL [Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] Generating outbound MDN, setting message id to "mendelson_opensource_AS2-COMMUN-1656496209296-20@XXXXXXXYYYYYYY".
[Jun 29, 2022, 11:50:09 AM] [mendelson_opensource_AS2-COMMUN-1656496209296-20@XXXXXYYYYYY] Outbound MDN has not been signed.
[Jun 29, 2022, 11:50:09 AM] [mendelson_opensource_AS2-COMMUN-1656496209296-20@XXXXXYYYYYY] Outbound MDN created for AS2 message "d7856e5d-f790-11ec-b644-000003c0e4e1@DCE", state set to [processed/error: authentication-failed].
[Jun 29, 2022, 11:50:09 AM] [d7856e5d-f790-11ec-b644-000003c0e4e1@DCE] Outbound MDN details: Error verifying the senders digital signature: Verification failed

Signature certificate information:
Serial number (DEC): 496287618
Issuer: C=IT,O=PPPPPPPPP,L=ZZZZZZ,OU=PPPPPPPPP,CN=XXXXXXXXXX

Verification certificate information:
Serial number (DEC): 16574464041134342424234324242342
Serial number (HEX): 54235435345345435435435435345345 Finger print (SHA-1): ZZ:Z::Z::Z::Z:
Valid from: 5/31/22
Valid to: 5/31/23
Issuer: CN=Certum Domain Validation CA SHA2, OU=Certum Certification Authority, O=Unizeto Technologies S.A., C=PL.
[Jun 29, 2022, 11:50:09 AM] [mendelson_opensource_AS2-COMMUN-1656496209296-20@XXXXXXXXZZZZZZZZZ] Synchronous MDN sent as answer to message d7856e5d-f790-11ec-b644-000003c0e4e1@DCE.