System.Xml.XmlException: '', hexadecimal value 0x1F, is an invalid character. Line 1, position 1.

[Denommus]

I get the following stacktrace when I try to run the GetCampaigns.cs example:

Unhandled Exception:
System.ApplicationException: Failed to retrieve campaigns ---> System.Xml.XmlException: '�', h
exadecimal value 0x1F, is an invalid character. Line 1, position 1.                          
  at (wrapper managed-to-native) System.Object:__icall_wrapper_mono_remoting_wrapper (intptr,i
ntptr)                                                                                       
  at (wrapper remoting-invoke) Google.Api.Ads.AdWords.v201710.CampaignServiceInterface:get (Go
ogle.Api.Ads.AdWords.v201710.Selector)                                                       
  at Google.Api.Ads.AdWords.v201710.CampaignService.get (Google.Api.Ads.AdWords.v201710.Select
or serviceSelector) [0x00006] in <d80844e303564a36a586d7dee85d4f6d>:0                        
  at Program.loopAction[a] (Google.Api.Ads.AdWords.v201710.CampaignService campaignService, Go
ogle.Api.Ads.AdWords.v201710.Selector selector) [0x00007] in <5a86d9fb98fea6e2a7450383fbd9865a
>:0                                                                                          
  at Program.main (System.String[] argv) [0x00076] in <5a86d9fb98fea6e2a7450383fbd9865a>:0 
   --- End of inner exception stack trace ---
  at Program.main (System.String[] argv) [0x0009b] in <5a86d9fb98fea6e2a7450383fbd9865a>:0 
[ERROR] FATAL UNHANDLED EXCEPTION: System.ApplicationException: Failed to retrieve campaigns -
--> System.Xml.XmlException: '�', hexadecimal value 0x1F, is an invalid character. Line 1, pos
ition 1.                                                                                     
  at (wrapper managed-to-native) System.Object:__icall_wrapper_mono_remoting_wrapper (intptr,i
ntptr)                                                                                       
  at (wrapper remoting-invoke) Google.Api.Ads.AdWords.v201710.CampaignServiceInterface:get (Go
ogle.Api.Ads.AdWords.v201710.Selector)                                                       
  at Google.Api.Ads.AdWords.v201710.CampaignService.get (Google.Api.Ads.AdWords.v201710.Select
or serviceSelector) [0x00006] in <d80844e303564a36a586d7dee85d4f6d>:0                        
  at Program.loopAction[a] (Google.Api.Ads.AdWords.v201710.CampaignService campaignService, Go
ogle.Api.Ads.AdWords.v201710.Selector selector) [0x00007] in <5a86d9fb98fea6e2a7450383fbd9865a
>:0                                                                                          
  at Program.main (System.String[] argv) [0x00076] in <5a86d9fb98fea6e2a7450383fbd9865a>:0 
   --- End of inner exception stack trace ---
  at Program.main (System.String[] argv) [0x0009b] in <5a86d9fb98fea6e2a7450383fbd9865a>:0 

[christopherseeley]

This sounds like issue #116 . Is gzip compression enabled? If so, set it to false:
https://github.com/googleads/googleads-dotnet-lib/blob/master/src/AdWords/App.config#L34

Alternatively, you can try .NET Core instead of mono, but see issues #133 and #134 to see if that's an option.