Hi Michael,
I am sorry for the delay in this reply.
I have checked the build log and it seems like the error is caused by the incorrect details of the .p12 file. Below is the exact error message that the server returned.
Invalid PKCS#12 (.p12) file: PKCS#12 MAC could not be verified. Invalid password?.
This could mean that the file itself is invalid or the .p12 password is entered incorrectly at Titan. Perhaps you can try to double-check the credentials details and recreate the files (both .p12 and provisioning profile) if necessary.