The Trump administration on Monday said it could not accept an Obamacare waiver from Massachusetts because officials from the commonwealth hadn't filed it sufficiently ahead of time.

Under Obamacare, applications for waivers, known as 1332 or "innovation waivers," must be filed to give federal health officials at least 180 days to review them, and must also undergo a public comment period. Massachusetts filed its waiver on Sept. 8 and wanted it to be approved before Nov. 1, when open enrollment begins.

Republicans have complained that the waiver process is burdensome, lengthy and prevents states from meeting the needs of their residents. Though the Trump administration had encouraged the use of such waivers, they said their hands were tied by Obamacare's requirements.

"Given that the waiver was submitted less than two months prior to the beginning of the 2018 open enrollment period and, if the application were deemed complete, the federal public comment period would not end until after the beginning of open enrollment, the departments have determined that there is not sufficient time to implement the proposed waiver," wrote Randy Pate, deputy administrator at the Centers for Medicare and Medicaid Services.

Upon hearing the news, Sen. Lamar Alexander, chairman of the Health, Education, Labor and Pensions Committee, said that if his Obamacare stabilization bill had been passed then Massachusetts waiver would have been accepted on time. His legislation would make changes to Obamacare's 1332 waivers that include allowing states to file for an expedited review that would last 45 days.

"Under the Alexander-Murray bill, states can get waivers approved in 45 days if the situation requires urgent action — so Massachusetts could have had its waiver approved by now to help reduce chaos when open enrollment begins next week," Alexander, R-Tenn., said in a statement. "This is further evidence that the Affordable Care Act needs changes and that states need our bill to get flexibility from the law."

Obamacare was modeled after the Massachusetts healthcare system. The waiver would have allowed the state to create a fund given to insurers rather than rely on cost-sharing reduction subsidies, which are paid by the federal government and allow insurers to lower out-of-pocket medical expenses for low-income enrollees. Trump abruptly cut off the funding last week, and the Alexander-Murray bill would seek to re-establish it for two year. The bill appears to have the 60 votes it would need to clear the Senate, but not full support of the House or the White House.

The Massachusetts waiver also requested some flexibility on the employer mandate, which requires that employers with 50 or more full-time workers provide medical coverage to their staff.