in the <>-castep_Efield.castep file

==============================================================================
+                           Vibrational Frequencies                          +
+                           -----------------------                          +
+                                                                            +
+ Performing frequency calculation at  1 wavevector  (q-pt )                 +
+ ========================================================================== +
+                                                                            +
???????????????????????????????????????????????????????????????????????
                     Warning in secondd_find_acoustics
    Failed to identify 3 eigenvectors with acoustic character
    Acoustic sum rule correction will only be applied to 2 mode(s)
????????????????????????????????????????????????????????????????????????
MPI Application rank 0 exited before MPI_Finalize() with status -107374181

Can anyone give me a hint how to solve the problem?

many thanks,

  Hao