QE error: "Error in routine electrons (1): charge is wrong: smearing is needed"

[KK M]

hi

I am trying to compute the band gap of a perovskite material using an SCF calculation in Quantum ESPRESSO, with the aim of obtaining the HOMO and LUMO energy levels.

From my understanding, this requires using
occupations = 'fixed' and avoiding smearing, so that the HOMO/LUMO positions are clearly reported in the output.

However, when I run the calculation with fixed occupations, the job stops with the error shown below. I have seen similar issues discussed on forums, but the suggested solutions or follow-up responses do not seem to work or are not applicable in my case.

Could someone please advise how to properly obtain the band gap (HOMO–LUMO / VBM–CBM) for this system in QE, and how to resolve this error?

My main goal is simply to obtain a reliable band gap value.

Thank you very much for your help.

----------------

WARNING: integrated charge=   162.30000000, expected=   163.00000000

 %%%%%%%%%%%%%%%%%%%
     Error in routine electrons (1):
     charge is wrong: smearing is needed
 %%%%%%%%%%%%%%%%%%%

The input file is given below: 

------------------------------

&CONTROL
  calculation = 'scf',
  prefix = 'CsInCoCl',
  outdir = './tmp/',
  pseudo_dir = '../pseudo/',
  nstep = 220
/
&SYSTEM
  ibrav = 0,
  nat = 19,
  ntyp = 4,
  ecutwfc = 60,
  ecutrho = 480,
  occupations = 'fixed',
  smearing = 'gaussian',
! ##  nbnd = 100
  degauss = 0.02,
! ##  nspin = 2
! ##  tot_magnetization = 0
/
&ELECTRONS
! ##  conv_thr = 1.0d-8,
! ##  electron_maxstep = 1800
/
ATOMIC_SPECIES
  In  114.81800  In.pbe-dn-rrkjus_psl.1.0.0.UPF
  Cs  132.90500  Cs_pbe_v1.uspp.F.UPF
  Cl   35.45150  cl_pbe_v1.4.uspp.F.UPF
  Co   58.93300  Co_pbe_v1.2.uspp.F.UPF
CELL_PARAMETERS (angstrom)
   7.571813080  -0.132121825   0.231085674
   3.736423790   6.588696575   0.236320072
  -3.396044913  -1.953146907  12.813041193
ATOMIC_POSITIONS (crystal)
Cs               0.6008970273        0.6010341843        0.8429458568
Cs               0.3991029727        0.3989658157        0.1570541432
Cs               0.8633574202        0.8634247571        0.5969810985
Cs               0.1366425798        0.1365752429        0.4030189015
In               0.2640073325        0.2641525866        0.8014974249
In               0.7359926675        0.7358474134        0.1985025751
Co               0.5000000000        0.5000000000        0.5000000000
Cl               0.3955472797        0.8008397079        0.5973136982
Cl               0.1991869568        0.6043698786        0.4026711893
Cl               0.6044527203        0.1991602921        0.4026863018
Cl               0.8008130432        0.3956301214        0.5973288107
Cl               0.3330204534        0.3330196647        0.6511648588
Cl               0.6669795466        0.6669803353        0.3488351412
Cl               0.1015477410        0.5984799430        0.8969172358
Cl               0.4016460362        0.8983774678        0.1030948105
Cl               0.8984522590        0.4015200570        0.1030827642
Cl               0.5983539638        0.1016225322        0.8969051895
Cl               0.0858875248        0.0860341558        0.8180093399
Cl               0.9141124752        0.9139658442        0.1819906601
K_POINTS automatic
6 6 3 0 0 0

regards