Invalid cast from 'System.String' to 'Sitecore.ContentSearch.IFieldMap' [closed]

Question

Sitecore version: 9.3

In my SOLR, the name of my master core is M7_master_index.

I am trying to get some result from Sitecore using search. So I am creating the SearchContext in the following ways:

using (var context = ContentSearchManager.GetIndex("M7_master_index").CreateSearchContext())
{
               
}

and

using (var context = ContentSearchManager.GetIndex("sitecore_master_index").CreateSearchContext())
{
               
}

But at ContentSearchManager.GetIndex() I am getting the following error:

"Invalid cast from 'System.String' to 'Sitecore.ContentSearch.IFieldMap'."

   at System.Convert.DefaultToType(IConvertible value, Type targetType, IFormatProvider provider)
   at Sitecore.Reflection.ReflectionUtil.SetProperty(Object obj, PropertyInfo property, Object value)
   at Sitecore.Reflection.ReflectionUtil.SetProperty(Object obj, String name, Object value)
   at Sitecore.Configuration.DefaultFactory.AssignProperties(Object obj, Object[] properties)
   at Sitecore.Configuration.DefaultFactory.AssignProperties(XmlNode configNode, String[] parameters, Object obj, Boolean assert, Boolean deferred, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateFromReference(XmlNode configNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateFromReference(XmlNode configNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.GetInnerObject(XmlNode paramNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.AssignProperties(XmlNode configNode, String[] parameters, Object obj, Boolean assert, Boolean deferred, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.GetInnerObject(XmlNode paramNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.AssignProperties(XmlNode configNode, String[] parameters, Object obj, Boolean assert, Boolean deferred, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper)
   at Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert)
   at Sitecore.ContentSearch.ContentSearchManager.get_SearchConfiguration()
   at Sitecore.ContentSearch.ContentSearchManager.GetIndex(String name)

Answer 1

Have been able to fix the issue. In the App.config default search engine was set to Azure which should not have been the case.