convergence of chemical shift calculus

[Francois Vivet]

I am a new user of VASP (5.3.3). I have been trying to perform calculus of chemical shift for 3 weeks now and I always get the same result (output of the bach) :
generate k-points for: 1 1 1
DFATOM: ERROR, unable to reach convergence in 100 cycles.

and the calculus stops whatever the value of ENCUT I choose or the way I build the K-points. Is someone abble to tell me what these 100 cycles are and which tag(s) I have to change to get a convergence of my calculus?
In addition, here is my INCAR file:
SYSTEM = (Sr Al2 O4)6 (P6_3) ~ (Pearson #1210460)_1 (VASP)

PREC = N
LCHIMAG =.TRUE.
ENCUT = 800.000
EDIFF = 1.0e-8
ISMEAR = 0; SIGMA = 0.1
DQ = 0.001
ICHIBARE = 1
LNMR_SYM_RED = .TRUE.
NSLPLINE = .TRUE.
LREAL = A
NBANDS = 142
NELMIN = 4
ISTART = 0

Best regards.

François Vivet

[admin]

Stopping criterion 1.0e-8 is very severe. Depending on the symetry of the system it can
be difficult to reach the convergence using 1.0e-8 withing a short time.
Try to preconverge the structure in several steps using milder criterion 1.0e-6, 1.0e-7.