Instability at a Joint in the MZ direction

Hello, 

I was carrying out an analysis for a frame and was informed of instability at a joint. Although i have two pinned joints in 3D model space , i have included releases to take care of out of plane moments and torsion on the top beam. However, the structure seems to be unresponsive and still shows up warnings of instability. Kindly help. 

STAAD SPACE GOAL POST ANALYSIS
START JOB INFORMATION
ENGINEER DATE 16-Jun-21
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0; 2 0 1.1 0; 3 0 0 2.8; 4 0 1.1 2.8;
MEMBER INCIDENCES
1 3 4; 2 4 2; 3 2 1;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+08
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-05
DAMP 0.03
TYPE STEEL
STRENGTH RY 1.5 RT 1.2
ISOTROPIC STEEL_275_NMM2
E 2.05e+08
POISSON 0.3
DENSITY 77
ALPHA 1.2e-05
DAMP 0.03
TYPE STEEL
STRENGTH FY 275000 FU 410000 RY 1.5 RT 1.2
END DEFINE MATERIAL
CONSTANTS
MATERIAL STEEL_275_NMM2 ALL
MEMBER PROPERTY BRITISH
1 TO 3 TABLE ST UC203X203X46
SUPPORTS
1 3 PINNED
MEMBER RELEASE
2 START MZ
2 END MZ
LOAD 1 LOADTYPE Dead TITLE DL1- PIPING AND FRAME S/W
SELFWEIGHT Y -1.1
MEMBER LOAD
2 CON GY -2.33 0.158 0
2 CON GY -0.27 0.533 0
2 CON GY -4.47 1.048 0
2 CON GY -0.66 1.625 0
2 CON GY -0.71 1.802 0
2 CON GY -0.65 1.981 0
2 CON GY -0.66 2.27 0
2 CON GY -0.23 2.464 0
2 CON GY -0.23 2.586 0
2 CON GY -0.25 2.924 0
LOAD 2 LOADTYPE Dead TITLE DL2 - CABLE TRAY LOAD
MEMBER LOAD
2 CON GY -3.5 1.5 0
LOAD 3 LOADTYPE Live TITLE LL1 - WATER LOAD
MEMBER LOAD
2 CON GY -1.4 0.158 0
2 CON GY -0.04 0.533 0
2 CON GY -3.68 1.048 0
2 CON GY -0.15 1.625 0
2 CON GY -0.15 1.981 0
2 CON GY -0.15 2.27 0
2 CON GY -0.16 1.802 0
2 CON GY -0.03 2.464 0
2 CON GY -0.03 2.586 0
2 CON GY -0.03 2.924 0
LOAD 4 LOADTYPE Live TITLE LL2 - THERMAL
MEMBER LOAD
2 CON GX -0.34 0.158 0
2 CON GX -0.03 0.533 0
2 CON GX -0.73 1.048 0
2 CON GX -0.07 1.625 0
2 CON GX -0.08 1.802 0
2 CON GX -0.07 1.981 0
2 CON GX -0.07 2.27 0
2 CON GX -0.02 2.464 0
2 CON GX -0.02 2.586 0
2 CON GX -0.03 2.924 0
LOAD 5 LOADTYPE Live TITLE LL3 - FRICTION
MEMBER LOAD
2 CON GX -0.9 0.158
2 CON GX -0.07 0.533
2 CON GX -1.96 1.048 0
LOAD COMB 6 SLS 1
1 1.0 2 1.0 3 1.0 4 0.6 5 0.6
LOAD COMB 7 SLS 2
1 1.0 2 1.0 3 0.6 4 0.6 5 1.0
LOAD COMB 8 ULS 1
1 1.35 2 1.35 3 1.5 4 0.9 5 0.9
LOAD COMB 9 ULS 2
1 1.35 2 1.35 3 0.9 4 0.9 5 1.5
LOAD COMB 10 ULS GEO
1 1.0 2 1.0 3 1.3 4 0.78 5 0.78
LOAD COMB 11 ULS GEO 2
1 1.0 2 1.0 3 0.78 4 0.78 5 1.3
PERFORM ANALYSIS
DEFINE ENVELOPE
6 7 ENVELOPE 1 TYPE SERVICEABILITY
8 9 ENVELOPE 2 TYPE STRENGTH
8 9 ENVELOPE 3 TYPE CONNECTION
10 11 ENVELOPE 4
END DEFINE ENVELOPE
PARAMETER 1
CODE EN 1993-1-1:2005
CHECK CODE ALL
PARAMETER 2
CODE EN 1993-1-1:2005
STEEL TAKE OFF ALL
FINISH