When investigating on dynamic environment setup and configuration on Azure. I came across an issue when Marketing Automation Engine worker process was going back to Pending restart state.
The Issue
The Sitecore Marketing Automation engine is not starting up. In spite of manually start again it going back to PendingStart state.

The Solution
First thing is to check the logs. When I see the logs for marketing automation engine webjob. It was having below given error message.
[11/24/2022 05:20:10 > 701b8b: SYS INFO] Run script 'Sitecore.MAEngine.exe' with script host - 'WindowsScriptHost'
[11/24/2022 05:20:11 > 701b8b: SYS INFO] Status changed to Running
[11/24/2022 05:20:11 > 701b8b: INFO]
[11/24/2022 05:20:11 > 701b8b: INFO] Starting Marketing Automation Engine...
[11/24/2022 05:20:12 > 701b8b: ERR ] ERROR
[11/24/2022 05:20:12 > 701b8b: ERR ] System.Xml.XmlException: Data at the root level is invalid. Line 1, position 1.
[11/24/2022 05:20:12 > 701b8b: INFO]
[11/24/2022 05:20:12 > 701b8b: ERR ] at System.Xml.XmlTextReaderImpl.Throw(Exception e)
[11/24/2022 05:20:12 > 701b8b: ERR ] at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitespace()
[11/24/2022 05:20:12 > 701b8b: ERR ] at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
[11/24/2022 05:20:12 > 701b8b: ERR ] at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace)
[11/24/2022 05:20:12 > 701b8b: ERR ] at System.Xml.XmlDocument.Load(XmlReader reader)
[11/24/2022 05:20:12 > 701b8b: ERR ] at System.Xml.XmlDocument.LoadXml(String xml)
[11/24/2022 05:20:12 > 701b8b: ERR ] at ?????????????????????????????????????????.?????????????????????????????????????????(????????????????????????????????????????? , String )
[11/24/2022 05:20:12 > 701b8b: ERR ] at ?????????????????????????????????????????..ctor(String )
[11/24/2022 05:20:12 > 701b8b: ERR ] at ?????????????????????????????????????????..ctor(String )
[11/24/2022 05:20:12 > 701b8b: ERR ] at Sitecore.XConnect.Configuration.Extensions.InitializeLicenseCheck(IServiceCollection collection, String licenseFileOrXml)
[11/24/2022 05:20:12 > 701b8b: ERR ] at Sitecore.XConnect.Configuration.Extensions.UseXConnectServiceInitializationConfiguration(IServiceCollection collection, IConfiguration configuration, String[] configurationSectionNames, String initializationSectionName, Boolean validateConfiguration)
[11/24/2022 05:20:12 > 701b8b: ERR ] at Sitecore.Xdb.MarketingAutomation.Engine.App.ServiceConfiguration.ConfigureServices(IConfiguration configuration, Boolean useDecorators)
[11/24/2022 05:20:12 > 701b8b: ERR ] at Sitecore.Xdb.MarketingAutomation.Engine.App.ServiceConfiguration.Reload()
[11/24/2022 05:20:12 > 701b8b: ERR ] at Sitecore.Xdb.MarketingAutomation.Engine.App.Program.RunAsConsoleApp(Boolean interactive)
[11/24/2022 05:20:12 > 701b8b: SYS INFO] Status changed to Success
[11/24/2022 05:20:12 > 701b8b: SYS INFO] Process went down, waiting for 60 seconds
[11/24/2022 05:20:12 > 701b8b: SYS INFO] Status changed to PendingRestart
At a first glance, above error message does not provide any valuable clue. But when read it fully and after few reads, found out the issue is related to license file. The InitializeLicenseCheck method indicate it clearly. Checked the license file on the MA engine job directory and the file contains only the text “LicenseContent” which is obviously not a valid xml format and there is no root element…!!!
In this Marketing automation Operations web app, there are two license files. One for the web application under the path <website root directory>\App_Data\license.xml and another one for MA engine worker job for which the path of license file is <website root directory>\App_Data\jobs\continuous\AutomationEngine\App_Data\license.xml.
Replace the content of both the license files with the correct license xml content. Stop and start the webjob and web application and the happy days…!!!!
Posting this message as I could not found any blog providing any solution about this error message. Hope this helps my fellow Sitecorians!