VXVM Strip volume extension

Hello,

I have the following issue.

sunstation1:/root# vxassist -g DG-DB001 maxsize
Maximum volume size: 326191104 (159273Mb)------------------------->It is showing that volume can be increased up to 159273Mb
sunstation1:/root#
sunstation1:/root#
sunstation1:/root# /etc/vx/bin/vxresize -g DG-DB001 VOL-DB001-data1 +50g
VxVM vxassist ERROR V-5-1-436 Cannot allocate space to grow volume to 1498001965 blocks
VxVM vxresize ERROR V-5-1-4703 Problem running vxassist command for volume VOL-DB001-data1, in diskgroup DG-DB001

Is it due to any internal restriction of the Volume manager.

regards

Arup