fence_vmware_soap stonith resource fails to start

Issue

After creating stonith resource it fails to start but all parameters such as user/password, IP address are valid and verified outside cluster and network connectivity is OK (it is possible to obtain status manually with command fence_vmware_soap). Cluster status shows stonith as stopped:

# pcs status
stonith-fence1 (stonith:fence_vmware_soap): Stopped 
stonith-fence2 (stonith:fence_vmware_soap): Stopped
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Failed Actions: * stonith-fence1_start_0 on node2 'unknown error' (1): call=680, status=Error, exitreason='none', last-rc-change='Tue Aug 22 10:41:07 2017', queued=0ms, exec=1215ms

Following errors can be observer in logs:

Aug 21 15:30:07 node2 fence_vmware_soap: Unable to connect/login to fencing device 
Aug 21 15:30:07 node2 stonith-ng[3202]: warning: fence_vmware_soap[44432] stderr: [ Unable to connect/login to fencing device ] 
Aug 21 15:30:07 node2 stonith-ng[3202]: warning: fence_vmware_soap[44432] stderr: [ ]
Aug 21 15:30:07 node2 stonith-ng[3202]: warning:fence_vmware_soap[44432] stderr: [ ]