Root element is missing.

Job started at 28/06/2020 11:50:52
Checking License ..
Job finished at 28/06/2020 11:50:53 done in 1s

Root element is missing.

at System.Xml.XmlTextReaderImpl.Throw (System.Exception e) [0x00027] in <4a776760e559455ead15edf260db6599>:0
at System.Xml.XmlTextReaderImpl.ThrowWithoutLineInfo (System.String res) [0x00017] in <4a776760e559455ead15edf260db6599>:0
at System.Xml.XmlTextReaderImpl.ParseDocumentContent () [0x0035d] in <4a776760e559455ead15edf260db6599>:0
at System.Xml.XmlTextReaderImpl.Read () [0x0008c] in <4a776760e559455ead15edf260db6599>:0
at System.Xml.XmlLoader.Load (System.Xml.XmlDocument doc, System.Xml.XmlReader reader, System.Boolean preserveWhitespace) [0x000a6] in <4a776760e559455ead15edf260db6599>:0
at System.Xml.XmlDocument.Load (System.Xml.XmlReader reader) [0x0002e] in <4a776760e559455ead15edf260db6599>:0
at System.Xml.XmlDocument.LoadXml (System.String xml) [0x00018] in <4a776760e559455ead15edf260db6599>:0
at  .–+ ..ctor (System.String , System.Boolean ,  .–+  ) [0x0001e] in <896f87e576a8482c8f603908a14ec73f>:0
at  .–..ctor (System.Collections.Generic.Dictionary`2[TKey,TValue] , System.Boolean , System.Boolean ) [0x001fa] in <896f87e576a8482c8f603908a14ec73f>:0
at  . ..ctor (System.String ) [0x012fb] in <896f87e576a8482c8f603908a14ec73f>:0
at  .―.  (System.String[] ) [0x00351] in <896f87e576a8482c8f603908a14ec73f>:0
Unhandled Exception
For detailed info, see log file /root/.wg++/WGLicense.log.txt
Execution stopped

mono version 6.10.0

this morning have this message when start wg++ 3.1

please any information why not work

regards