Stuck on resync

I have created a automation using C# that call out this function. the code is suppose to resync the sandboxpath provided.

string sCommandText = "si resync " +
                                      " --hostname=" + this.Server +
                                      " --port=" + this.Port +
                                      " --user=" + this.Username +
                                      " --password=" + this.Password +
                                      " --nooverwriteUnchanged " +
                                      "--yes " +
                                      "--confirm " +
                                      "--sandbox=" +
                                      sandboxPath + "\\project.pj";

 if (0 == iProcessHandler("cmd.exe", "/c " + sCommandText, ref sOutput, ref err))
                {
                    result = true;
                }
            }
            else
            {
                //Error Handling
            }
            return result;

the result of sCommandText is as follow (port ,username and password have been star out )"si resync  --hostname=ims-id --port=**** --user=******\t --password=******* --nooverwriteUnchanged --yes --confirm --sandbox=C:\\Users\\admin\\Desktop\\ACGC\\Sandbox\\AC\\project.pj"

the issues is that the code when called out get stuck on the command  "if (0 == iProcessHandler("cmd.exe", "/c " + sCommandText, ref sOutput, ref err))" and does not return back to the program at all (for an indefinite amount of time) manual resync on IMS for the sandbox folder work perfectly fine and also if the user manually type into a cmd "si resync  --hostname=ims-id --port=**** --user=****** --password=********* --nooverwriteUnchanged --yes --sandbox=C:\Users\admin\Desktop\ACGC\Sandbox\GC\project.pj" the resync work too. I have no idea what the issue here. Please Help 🙂