LINQ Query getting timedOut - performance

Question

I have getting following error message in my custom log file :
2018-03-07 15:40:51,897 ERROR - The request channel timed out while waiting for a reply after 00:01:59.9880000. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout.
mscorlib
Server stack trace:
at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
at System.ServiceModel.Channels.SecurityChannelFactory`1.SecurityRequestChannel.Request(Message message, TimeSpan timeout)
at System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message message, TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)
Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at Microsoft.Xrm.Sdk.IOrganizationService.Execute(OrganizationRequest request)
at Microsoft.Xrm.Sdk.Client.OrganizationServiceProxy.ExecuteCore(OrganizationRequest request)
at Microsoft.Xrm.Sdk.Client.OrganizationServiceProxy.Execute(OrganizationRequest request)
at Microsoft.Xrm.Sdk.Client.OrganizationServiceContext.Execute(OrganizationRequest request)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.RetrieveEntityCollection(OrganizationRequest request, NavigationSource source)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.Execute(QueryExpression qe, Boolean throwIfSequenceIsEmpty, Boolean throwIfSequenceNotSingle, Projection projection, NavigationSource source, List`1 linkLookups, String& pagingCookie, Boolean& moreRecords)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.Execute[TElement](QueryExpression qe, Boolean throwIfSequenceIsEmpty, Boolean throwIfSequenceNotSingle, Projection projection, NavigationSource source, List`1 linkLookups)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.Execute[TElement](Expression expression)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.GetEnumerator[TElement](Expression expression)
at Microsoft.Xrm.Sdk.Linq.Query`1.GetEnumerator()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at ACE.Crm.Business.Logic.CustomerCommunicationsLogic.RetrieveCustomers() in C:\Dev\Crm\Active\Src\ACE.Crm.Business\Logic\CustomerCommunicationsLogic.cs:line 541
This is all happening due to one filter condition in LINQ :
var list = (
from c in _crmRepository.Query<Contact>()
join cn in _crmRepository.Query<Connection>() on c.ContactId equals cn.Record1Id.Id
join a in _crmRepository.Query<Account>() on cn.RecordId2.Id equals a.AccountId.Value
where c.StateCode.Value == (int)ContactState.Active
&& cn.StateCode.Value == (int)ConnectionState.Active
&& c.BirthDate != null
&& a.ace_NetworkClient.GetValueOrDefault()
select new ReturnedCustomerDataClass
{
AccountId = a.AccountId.GetValueOrDefault(),
ContactId = c.ContactId.GetValueOrDefault(),
aceContactId = c.ace_ContactID,
<<<<<<< Many Other Fields>>>>>>>>>>>
}
In Where Clause you can see a filter a.ace_NetworkClient.GetValueOrDefault().
When I am removing this filter my query is not responding and being stuck. Can any one suggest me what is going wrong if I am removing filter && a.ace_NetworkClient.GetValueOrDefault() {ace_NetworkClient is a boolean field}.
In my result I wanted both customer for whom ace_NetworkClient flag is true or false thats why I removed that existing condition, getting proper result for local Org. but failing in production org due to large data.
Thanks