Good morning,
I’ve already asked this question on Microsoft Dynamics AX Community, but unfortunately the problem is still not resolved. I thought perhaps you, guys, will have some bright ideas? 
So please find the copy of original problem description below:
"I’ve been trying to solve this problem for the last few days. I got Enterprise Search (ES) working once, after I re-creating whole Search Service Application, but then it stopped working properly for some reason. If anyone is interested, all my experiences of getting AX 2012 to work with SharePoint Foundation 2013 are described here.
Ok, back to problem. What I have now is partially working search. By partially I mean, that if I type some general search term, such as ‘products’ results are being returned to me. However, when I try to use some more specific term, such as customer name or product code, it gives me Microsoft.Office.Server.Search.Query.InternalQueryErrorException error. After checking ULS report I stumbled upon this line:
01/30/2015 08:40:41.48 NodeRunnerQuery1-241c58d6-eafb- (0x0E20) 0x1108 Search Query Processing ak8rm Unexpected Microsoft.Office.Server.Search.Query.Ims.Security.SecurityTrimmerPostProducer : Post-Trimmer failed. Message: The shim execution failed unexpectedly - Exception occurred on the metadata service on client or server. See exception details below: >Unable to log on to Microsoft Dynamics AX… Trimmer: 601 c9c2e49c-87fa-80ce-41b7-5e85df196de8
I run out of ideas now, because it seems that I’ve tried almost everything what has been suggested on different forums to resolve similar issues. Perhaps someone could share their list of ‘should be dones’, which I could follow and see if I missed something here?"
Thank you!