The package of the EU-Turkey agreement to solve the refugee crisis was tied to visa liberalisation, to ease the deal for Turkey. This was what Turkey’s Prime-Minister Davutoglu’s achieved during the negotiations

After that the Turkish President took the decision to change the Prime-Minister. Meanwhile it seems that Erdogan is proposing his own son as a candidate.
by
N. Peter Kramer
Although throughout the EU-Turkey talks President Erdogan has continuously repeated that he was not willing to change laws in order to meet the agreement, it has not prevented the EU from setting dates. European Commission President Jean-Claude Juncker warned Erdogan that the agreement aiming to allow Turkish citizens visa-free travel within Europe will collapse if Turkey doesn’t fulfil its commitments.
However, President Erdogan refused to change the Turkish laws on terrorism, a main part of the deal, and let Juncker know ‘since when are you running this country? Who has given you the authority?'. After that the Turkish President took the decision to change the Prime-Minister. Meanwhile it seems that Erdogan is proposing his own son as a candidate.
Davutoglu’s departure coincided with the postponement of the visa liberalisation deal. European Parliament President Martin Schulz announced that he didn’t send the draft for the visa liberalisation tot the relevant parliamentary committee review. The reason he gave, was that Turkey has not fulfilled all the requirements.
Apart from the anti-terror law, there are other obstacles, about anti-corruption laws, data protection rules, and Europol and judicial cooperation. On this last one, Turkey must cooperate closely with all 28 EU member states, including Cyprus…
Now, the Commission tries to save the agreement quietly. If the negotiations are not successful, there will be more delay and it could ultimately end in a catastrophic failure: with again a major influx of migrants arriving to the Greek islands, as it happened in 2015.