convergence not achieved

[Isha]

hi everyone!
i m a beginner in vasp.i am trying to optimize clusters.here is my INCAR.actually i want to calculate magnetic moment of clustersafter optimization.this is specific incar for Mn3(manganese trimer).
PREC = MED
SYSTEM = Mn3
ISTART = 0
ICHARGE = 2
ISPIN = 1
NELM = 70
NSW = 50
IBRION = 1
ISYM = 0
POTIM = 0.6
AMIX = 0.02
BMIX = 0.00001
ENCUT = 337.3
NBANDS = 19
LDIAG = .TRUE.
IALGO = 48
ADDGRID = .TRUE.
ISMEAR = -1
SIGMA = 0.02
EDIFF = 0.00001
EDIFFG = -0.005

I have tried with ibrion =2 alsoi have changed the values of potim,ismear and sigma.With the help of earlier seen forum reports ,i have modified my incar but no result reaching to convergence.
i am using gamma points and PAW_GGA potential.
my POSCAR is given below
Mn3
1
10 0 0
0 10 0
0 0 10
cart
3.0 3.0 3.0
5.8 3.0 3.0
4.5 5.4 3.0


please help me if anyone can, as i am having the same problem with Germanium clusters.nobody is here to help me.please help me,what is wrong here.

thank you so much in advance
regards

[admin]

you will certainly not obtain any magnetic properties (and the run will probably not converge) if you set ISPIN=1.
please either use ISPIN=2 (collinear magnetism) or LNONCOLLINEAR=.true. (non-colllinear)
also, it may improve convergence if you give some reasonable magnetic moment
(MAGMOM) for the Mn atoms in INCAR