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May 2023 Dark Days for CMS Data Center Migration – Rescheduled May 2023 Dark Days for Data Center Migration

As we previously communicated, the Medicare Part A CMS Data Center Migration was postponed. The new date for the migration is scheduled for 5/19/2023 to 5/22/2023 with a cut-over to the new data center on 5/23/2023. All systems and IVR will be available on 5/23/2023.

CMS will be migrating to the Kent Data Center in May 2023. As a result, National Government Services will be observing a series of dark days to accommodate the anticipated duration of this activity and to ensure the completion of weekly/monthly/quarterly processing and the migration of the data center.

These dark days will limit access to information provided by the IVR system, our self-service portal, NGSConnex, as well as EDI. Providers may experience limited or no access to claim status, eligibility, reopening/appeal status and financial claim information. Please see the list below of the functionality and its availability.


Please continue to use Option 5, starting 5/23/2023 use Option 2. Note: claim submission will not be available from Friday evening, 5/19/2023 through Monday, 5/22/2023.

Dark Days

Medicare Part A

  • The weekend of 5/20/2023 to 5/21/2023, starting on Friday evening, 5/19/2023 Part A (FISS) production cut-over.
  • Monday, 5/22/2023 – MAC dark day to support the completion of the migration to new data center.

Provider Contact Center

In addition, while our Provider Contact Center will be open, the systems used to handle claim specific questions will not be available. During this time, our staff will be limited to general questions so please plan accordingly. 

Service Availability


IVR Functionality Available during the Migration:

  • Eligibility <1>
  • Provider Enrollment <5>
  • General Information<8>
  • Other Options <9>

 IVR Functionality NOT Available during the Migration:

  • Claim Status <2>
  • Checks <3>
  • Remittance Statements <4>
  • Patient Status <6>
  • Appeal Status <7>


Part A Available in NGSConnex during the Migration:

  • Eligibility (Please note Patient Status will not be available. Patient Status is located under the Eligibility Lookup tab and will not be available but the other Eligibility functionality will be available.)
  • ADR
  • General Inquiries
  • A&R Inquiries (Part A Only)
  • A&R Document Submission (Part A Only)
  • MBI Lookup
  • Remittance
  • Prior Authorization
  • Credit Balance Reports (Part A Only)
  • Outstanding Overpayments
  • 1099s

Part A NOT Available in NGSConnex during the Migration:

  • Patient Status Lookup
  • Claim Status Lookup
  • Appeal/Reopening Submission
  • Appeal/Reopening Status
  • Checks/EFT
  • FCN Claim Detail Search (Part B Only)
  • FCN Beneficiary Search (Part B Only)
  • Provider Earnings to Date (Part B Only)
  • Special Checks (Part B Only)


  • Providers/Trading Partners can continue to send claims during the migration timeframe and the dark days. The 999 (Acknowledgement) and 277CA (Claims Acknowledgement report) will be generated.
  • Providers/Trading Partners can continue to send claim status requests however, the real time and batch responses may be delayed.
  • Medicare Part A DDE will not be available over the migration weekend and dark days.
  • Medicare Part A 835/Remittances will be available Saturday morning 5/20/2023; however, no 835/Remittances will be available on Tuesday morning 5/23/2023. On Wednesday, 5/24/2023 835/Remittances will resume normal delivery times.
  • Providers/Trading Partners can continue to send the X12 275 for Electronic Attachments during the migration timeframe and dark days. The 999 will be generated, no delayed timeframe.
  • Providers/Trading Partners can continue to use the EDI Enrollment tool available on the NGS website. We do not expect a delay with the NGS response/set up for EDI enrollment.
  • EDI Help Desk will be available to assist providers/Trading Partner’s during normal business hours, however data may be limited.

We encourage our provider community to register for NGS Email Updates to receive important information about the Medicare Program and upcoming training opportunities. Visit our website to subscribe to our Email Updates and receive upcoming News.

Posted 5/10/2023