On September 25th, the ambassadors from France, Germany, Britain and the EU stated that the Trump administration’s discomfort with the Iran nuclear deal is not accepted by them.

The terms of the agreement state that Iran will eliminate its stockpile of medium-enriched uranium, decrease its stockpile of low-enriched uranium by 98%, reduce the number of its gas centrifuges by about two-thirds for 13 years, and not build any new heavy-water facilities for the same period of time. Uranium-enrichment activities will be limited to a single facility using first-generation centrifuges for 10 years. For the next 15 years enriching uranium only up to 3.67% is permissible.

To make sure that Iran is compliant with the deal, the International Atomic Energy Agency (IAEA) has regular access to all Iranian nuclear facilities. In exchange for that, Iran will get relief from economic sanctions from the U.S., the European Union and the United Nations Security Council nuclear-related economic sanctions.

The reason for that disagreement is the belief in the international community that Iran is holding up its end of the deal. The International Atomic Energy Agency (IAEA) confirmed last month for the eighth time that Iran has been compliant.
Another thing is the fact that the facilitation of that deal was a humongous labor that brought together unwilling partners, like Russia and China, and most importantly Iran itself.