SEC Won't Open Post 5.5.2 Upgrade

Upgraded to 5.5.2 and now attempts to open SEC fail. I've found what I believe is a relevant log snippet:

 

2020-07-21 15:35:29,592 [11] [(null)] WARN  {SophosManagementSecurity.LogWarning} ==> The SEC permissions cannot be retrieved for the user : CYPHERSYSTEMS\[redacted]
2020-07-21 15:35:29,592 [11] [(null)] WARN  {SophosManagementSecurity.LogWarning} ==> Cannot communicate with management service [Reason = System.Runtime.InteropServices.COMException (0x800706BA): The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
   at ManagementServiceLib.CoreServicesClass.getSubEstates(String username)
   at Sophos.Management.Security.RoleBaseAdministrationAdaptor.<>c__DisplayClass7_0.<FetchAndVerifyUserSubEstate>b__0()
   at Sophos.Management.Security.RoleBaseAdministrationAdaptor.InvokeManagementServiceOperation[T](Func`1 func, String machineUserName, Int32 numberOfRetries)], it might have been restarted, hence re-creating management service.
2020-07-21 15:35:29,592 [11] [(null)] WARN  {SophosManagementSecurity.LogWarning} ==> System.Runtime.InteropServices.COMException (0x800706BA): The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
   at ManagementServiceLib.CoreServicesClass.getSubEstates(String username)
   at Sophos.Management.Security.RoleBaseAdministrationAdaptor.<>c__DisplayClass7_0.<FetchAndVerifyUserSubEstate>b__0()
   at Sophos.Management.Security.RoleBaseAdministrationAdaptor.InvokeManagementServiceOperation[T](Func`1 func, String machineUserName, Int32 numberOfRetries)