On or about the middle of March 2019, the SC Geodetic Survey moved the location of the differential correction files, needed to post-process GNSS data, to a new server. Users of Trimble Pathfinder Office or Trimble Positions Desktop may download a new user list from our Success Center. Feel free to contact me directly for the list or for access to our Success Center.
While your receiver may also include Glonass satellites, there are no correction files available for Glonass between middle of March through March 19th. Therefore, you should choose the non-Glonass choice (dat file) for these dates. Files that include Glonass are available after March 19th.
An example of non-Glonass choice: