The current crisis has its roots in the events of 2014. The six members of the GCC had split into two groups, the Saudi aligned group (Saudi Arabia, UAE and Bahrain) and the unaligned group (Oman, Kuwait and Qatar).
What really split the GCC was the election of Egyptian President Mohamed Morsi, in June 2012 with the strong support of the Muslim Brotherhood. A stated in Wikipedia:
Morsi has seen strong support from Qatar, which has maintained long-held ties with the Muslim Brotherhood, of which Morsi was a member until his election. Qatar has declared that it would provide Egypt with US$2 billion just as Morsi announced the reshuffle in the cabinet on 12 August 2012. Meanwhile, investors from Qatar have pledged to invest 10 billion in Egyptian infrastructure.
As stated in the Al Jazeera article:
Along with the general challenge of change and support for democratisation, the rise of the Muslim Brotherhood movement, was seen as undermining the legitimacy and potentially the political stability of some of the GCC states. While some of the GCC countries embarked on a quest to counteract the revolutions, and to contain the changes they had given birth to, Qatar supported the uprisings, as well as their effects on the region’s politics, economics and press freedom.
Qatar’s support for the uprisings clashed head-on with the policies and efforts of other GCC states. Thus, the Riyadh meeting and first agreement were an attempt by GCC states to discourage Qatar from pursuing its policies on the Arab Spring. When Qatar continued supporting the popular movements and uprisings, the withdrawal of ambassadors represented a kind of political censure, urging Doha to stop acting in ways that conflicted with the interests of other GCC states.
Arab Spring resulted in violence in many of the Arab countries, and the overthrow of four governments: Tunisia, Egypt, Libya and Yemen. It is beyond the scope of this blog to go back to December 18, 2010, but it has to be one of the most incredible stories in recent time, of how one push cart vendor in Tunisia ignited rebellions in throughout the Arab world which in the case of the Syrian civil war, continue until today.
A Wikipedia link is provided on the Muslim Brotherhood, and a commentary of the growing antagonism between Egypt and Saudi Arabia with Qatar’s support of the Muslim Brotherhood and other organizations, Hamas and Hezbollah.
There were many other events causing tensions in the area. Certainly, President Obama’s Iran nuclear arms deal was a concern to Saudi Arabia. Donald Trump’s visit in 2017 to Saudi Arabia was likely considered a positive, as the focus was to single out Iran as the state sponsor of terrorism. Qatar with its close relation to Iran, could be seen as aiding and abetting the enemy.
Trump’s speech in Saudi Arabia seemed to avoid the most critical elements of ISIL terrorist activities in European countries, in which Muslims had become radicalized through “hate propaganda” aimed at taking advantage of their feelings of isolation and non-acceptance in society.
Wikipedia: Muslim Brotherhood
National Interest: Qatar vs. Saudi Arabia
Washington Post: How Saudi Arabia played Trump’s Visit