"The cancellation comes after Mexico’s government denounced Trump’s new border security measures aimed at interfering with the cash flow of the very Mexican cartels believed to have financed the current Mexican president’s campaign."  

Trump specifically called out Mexican cartels in the executive order. In response to the anti-cartel measures, Peña Nieto took to social media.

In addition to denouncing the measure, Peña Nieto announced that he would be ordering the 50 Mexican Consulates in the U.S. to step up their efforts to protect “migrants”. The Mexican president made no mention of the fact that the migrants are one of the largest funding mechanisms for the cartels who reportedly helped him gain his office." http://www.breitbart.com/big-government/2017/01/26/mexican-president-cancels-u-s-trip/