From the linked article:

Each time Mr. Boehner arrived at the White House for an event, the president would pull him aside and ask about immigration, according to White House and Republican aides. Mr. Boehner urged patience, saying there was a “narrow path” to get something done, despite opposition in his party from what Republican aides call the “boxcars crowd,” a reference to conservative members who favor deportation for most of the 11 million.