Hello team, I keep getting a toast message saying 'Manifest was malformed' when I try to login to the Field Service Mobile app for a user on our Dev Sandbox environments. I don't get the same error when using another QA Sandbox environment. I have attached a snippet of the error log (Copilot says the server is getting HTML response instead of javascript) but it doesn't give a stack trace from which I could figure out where exactly the failure lies. Following are my troubleshooting steps so far:
- Uninstall and re-install the app from Playstore for my Android device
- Clear Cache and cookies, hard close, and re-open app and re-login
- Deactivate and Re-activate the Service Resource, ensure it is linked to the correct User
- Create a new Service Resource linked to a new user
- Check the Field Service Mobile app builder config and compare it with the config on the QA Sandbox
- Check the Field Service Mobile settings and compared it to the settings on QA Sandbox
Error log snippet: 2026-07-27T01:55:51.708Z W/BootstrapHostApp: Failed to downloadApp com.salesforce.lightning.mobileruntime.download.DownloaderException$InvalidData: Manifest was malformed at com.salesforce.lightning.mobileruntime.download.ManifestDownloader.fetchManifest(Unknown Source:128) at com.salesforce.lightning.mobileruntime.download.ManifestDownloader$fetchManifest$1.invokeSuspend(Unknown Source:12) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(Unknown Source:10) at kotlinx.coroutines.UndispatchedCoroutine.afterResume(Unknown Source:30) at kotlinx.coroutines.AbstractCoroutine.resumeWith(Unknown Source:13) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(Unknown Source:46) at kotlinx.coroutines.UndispatchedCoroutine.afterResume(Unknown Source:30) at kotlinx.coroutines.AbstractCoroutine.resumeWith(Unknown Source:13) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(Unknown Source:46) at kotlinx.coroutines.DispatchedTask.run(Unknown Source:128) at kotlinx.coroutines.internal.LimitedDispatcher$Worker.run(Unknown Source:3) at kotlinx.coroutines.scheduling.TaskImpl.run(Unknown Source:2) at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(Unknown Source:0) at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(Unknown Source:33) at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(Unknown Source:28) at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(Unknown Source:0) Caused by: kotlinx.serialization.json.internal.JsonDecodingException: Unexpected JSON token at offset 2: Expected start of the object '{', but had '<' instead at path: $ JSON input: <!DOCTYPE HTML PUBLIC "-//W3C/..... at kotlinx.serialization.json.internal.JsonExceptionsKt.JsonDecodingException(SourceFile:3) at kotlinx.serialization.json.internal.JsonExceptionsKt.JsonDecodingException(SourceFile:10) at kotlinx.serialization.json.internal.AbstractJsonLexer.fail(Unknown Source:51) at kotlinx.serialization.json.internal.AbstractJsonLexer.fail$default(Unknown Source:14) at kotlinx.serialization.json.internal.AbstractJsonLexer.unexpectedToken(Unknown Source:103) at kotlinx.serialization.json.internal.StringJsonLexer.consumeNextToken(SourceFile:14) at kotlinx.serialization.json.internal.StreamingJsonDecoder.beginStructure(Unknown Source:22) at com.salesforce.lightning.mobileruntime.bootstrap.json.BootstrapManifest$$serializer.deserialize(SourceFile:1) at com.salesforce.lightning.mobileruntime.bootstrap.json.BootstrapManifest$$serializer.deserialize(SourceFile:2) at kotlinx.serialization.json.internal.StreamingJsonDecoder.decodeSerializableValue(Unknown Source:314) at kotlinx.serialization.json.Json.decodeFromString(SourceFile:3) at com.salesforce.lightning.mobileruntime.bootstrap.json.BootstrapManifest$Companion.fromJson(Unknown Source:20) at com.salesforce.lightning.mobileruntime.download.ManifestDownloader.fetchManifest(Unknown Source:104) ... 15 more 2026-07-27T01:55:51.713Z E/LdsEnvironmentManagerImpl: LDS bootstrap failed com.salesforce.lightning.mobileruntime.download.DownloaderException$InvalidData: Manifest was malformed at com.salesforce.lightning.mobileruntime.download.ManifestDownloader.fetchManifest(Unknown Source:128) at com.salesforce.lightning.mobileruntime.download.ManifestDownloader$fetchManifest$1.invokeSuspend(Unknown Source:12) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(Unknown Source:10) at kotlinx.coroutines.UndispatchedCoroutine.afterResume(Unknown Source:30) at kotlinx.coroutines.AbstractCoroutine.resumeWith(Unknown Source:13) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(Unknown Source:46) Thanks in advance team, any help is greatly appreciated. - Swapnil @* Salesforce Field Service *
Hello team, I got help from Salesforce Support regarding this. I had to change the 'Session Security Level Required at Login' option under Profile from 'High Assurance' to None. The Desktop login worked fine for the user, just the app login kept failing.
