The key objectives of the JCPOA were as follows:

Limiting Uranium Enrichment: Iran agreed to reduce its stockpile of enriched uranium by 98% and limit its uranium enrichment to 3.67% for a period of 15 years. This significantly extended the time it would take for Iran to develop enough fissile material for a nuclear weapon.

Enhanced Monitoring and Verification: The International Atomic Energy Agency (IAEA) was granted extensive access and monitoring rights to Iran's nuclear facilities. This allowed for regular inspections and verification of Iran's compliance with the agreement.

However, in May 2018, the United States under the administration of President Donald Trump unilaterally withdrew from the JCPOA and reimposed sanctions on Iran. The primary reasons for the U.S. withdrawal were as follows:

Concerns about Non-Nuclear Activities: The United States criticized the JCPOA for not addressing Iran's ballistic missile program, regional influence, and alleged support for terrorist organizations. The U.S. argued that these issues should have been included in the agreement.

Sunset Provisions: The JCPOA had certain limitations on Iran's nuclear activities that were time-limited. The U.S. administration raised concerns that once these limitations expired, Iran would be free to pursue nuclear weapons capabilities.

Conclusion

Conclude your answer in a short and simple way by understanding the demand of the question

The U.S. withdrawal from the JCPOA created significant tensions between Iran and the remaining parties to the agreement. Iran gradually scaled back its compliance with certain provisions of the deal, citing the failure of other parties to uphold their commitments. Efforts to salvage the agreement have continued, with ongoing negotiations between Iran, the European Union, and the other remaining parties, but the future of the JCPOA remains uncertain.