IOS/Xcode error when using System.net.mail

Unity Engine
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1

Hey all, I’ve stumbled upon an issue with sending smtp mail via my apps. The Android and desktop versions work fine however IOS does not. It also doesn’t crash, it simply does nothing. So I debugged it in Xcode and found it outputting the following error report. I have no idea why this is and what it means.
Has anyone else encountered anything like this and know what may be causing it? Any help/ advice would be a huge help as I really don’t know what to do next. I can provide more information if required. Thanks in advance
(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/UnityEngineDebugBindings.gen.cpp Line: 65)

MissingMethodException: Method not found: ‘Default constructor not found…ctor() of System.Net.Configuration.MailSettingsSectionGroup’.

at Mono.Security.Uri.HexEscape (Char character) [0x00000] in :0

at System.Activator.CreateInstance (System.Type type, Boolean nonPublic) [0x00000] in :0

at System.Configuration.ConfigInfo.CreateInstance () [0x00000] in :0

at iTween.easeInOutElastic (Single start, Single end, Single value) [0x00000] in :0

at System.Configuration.Configuration.GetSectionGroupInstance (System.Configuration.SectionGroupInfo group) [0x00000] in :0

at System.Configuration.ConfigurationSectionGroupCollection.get_Item (System.String name) [0x00000] in :0

at System.Configuration.Configuration.GetSection (System.String path) [0x00000] in :0

at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection (System.String configKey) [0x00000] in :0

at System.MonoInternalNoteAttribute…ctor (System.String comment) [0x00000] in :0

at System.Configuration.ConfigurationManager.GetSection (System.String sectionName) [0x00000] in :0

at System.Net.Mail.SmtpClient…ctor (System.String host, Int32 port) [0x00000] in :0

at System.Net.Mail.SmtpClient…ctor (System.String host) [0x00000] in :0

at mono_gmail.SendCableDesignMail (System.String email, System.String cableLength, System.String colorCode) [0x00000] in :0

at PostSubmissionData+c__Iterator0.MoveNext () [0x00000] in :0

at System.Collections.Generic.Dictionary2+Transform1[System.Int32,UnityEngine.EventSystems.PointerEventData,System.Collections.Generic.KeyValuePair`2[System.Int32,UnityEngine.EventSystems.PointerEventData]].EndInvoke (IAsyncResult result) [0x00000] in :0

System.Collections.Generic.Transform`1:EndInvoke(IAsyncResult)

(Filename: currently not available on il2cpp Line: -1)

2

@Axcell_Hunt

My suspicion is that the constructor for the System.Net.Configuration.MailSettingsSectionGroup is being stripped out, since it is accessed via reflection. With the IL2CPP scripting backend, stripping is always enabled, so this might happen.

You can attempt to require this type to not be stripped by using a link.xml file, as described here:

http://docs.unity3d.com/Manual/iphone-playerSizeOptimization.html

3

I get the same error when trying to send an email from iOS(works great on Android and Unity Editor).

I tried Josh’s solution but it’s not working. Have you solved this problems somehow? Thanks!

4

@danieltranca_1

You might be experiencing this bug:

http://issuetracker.unity3d.com/issues/il2cpp-crashes-when-using-smtpclient

Note that we do have a more complex work around than I one I suggested earlier on this thread. You can use this link.xml file:

Once we correct this issue, you won’t need this link.xml file, but we’ve not been able to complete the fix yet.

2 Likes
5

Quick addition for devs getting here via search: In newer versions of Unity you have to add an additional line to link.xml:

3 Likes
6

I also need to add the namespace to my c# script

using System.Net.Configuration
7

You guys in this thread are the best. <3

Just incase anyone else comes here, when I pasted this additional line into xcode it gave me a weird character, which when I built meant the fix didn’t work, you have to select the character and delete that and nothing else, then the fix will work.

Thanks for all the info guys, I’m gonna look into stripping now (engine stripping that is…) godspeed to all of you!

Tom

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9

Greetings. I have the problem of not being able to send email on the iOS platform, I see that in this thread you comment that creating a link.xml with the references that you indicate is solved, I have created the file and I have placed it in the asset folder but I compile the project and still not send, I have to save it in another folder? or select some spices configuration so that link.xml does its function ?, thanks.

10

The link.xml file should work when it is placed in the Assets folder. You can find all of the details in the documentation here: https://docs.unity3d.com/Manual/IL2CPP-BytecodeStripping.html

When the mail does not send, do you see an error message? If not, this might be a different issue from the one originally mentioned in this thread.

1 Like
11

same issue here, didn’t see it at first since xcode wasn’t showing the symbol.

12

It’s working when stripping set only to low, which makes the size of the app ridiculously large. When setting stripping to higher level, the mail does not send, there are no errors, and the success callback is sent, but nothing arrives in the mail. Is there a way to investigate this issue?

13

I’m not familiar enough with the class library mail code to venture a guess, unfortunately. You could try to debug the generated C++ code - but without an understanding of how the C# code should work, that might be difficult.

Another option is to diff the stripped assemblies in the case that works and the case that does not work - maybe something in the mail code in the class libraries will jump out as missing. Then you could use a link.xml to preserve that.