First, do these in office web apps server
new-officewebappsfarm -Verbose -InternalURL http://192.168.100.149 -ExternalURL http://192.168.100.149 -AllowHTTP -ClipartEnabled -TranslationEnabled -EditingEnabled new-officewebappsfarm -Verbose -InternalURL http://sharepoint2013owa.petersoft.com -ExternalURL http://sharepoint2013owa.petersoft.com -AllowHTTP -ClipartEnabled -TranslationEnabled -EditingEnabled
Second, do these in sharepoint server
Remove-SPWOPIBinding -All:$true New-SPWOPIBinding -ServerName sharepoint2013owa.petersoft.com -AllowHTTP