SAP Message 26085 - Document & locked by & (object link not possible now)

Diagnosis You want to link an SAP object (for example, material master) todocument &V1&. User &V2& is currently processing document &V1&, so you cannot createthis link right now. Procedure Please try again later. If the document is locked over a long period oftime, contact user &V2& to find out why.