The Information Model Server (IMS) is part of the Reference Runtime Environment (RRTE). It is used to provide data to an OPC UA Client, but sometimes this fails as the IMS is not detected and, as a result, unreachable by any connection. 

This happens if the IMS is not loaded into memory during the start of the RRTE. This can be validated via the MS-Windows Task manager. If the RRTE is loaded and there is no 32bit-process “InformationModelServer.exe” listed in the Task manager, your PC is affected by this issue. 

To bypass this Issue, please close the RRTE and start it again with administrator access rights.