Anne Yang Take a look https://knowledge1.thermofisher.com/Mass_Spectrometry/Mass_Spectrometry_Knowledge/XCalibur_Software_Not_Connected_and_Acquisition_Server_Error
Kindly see also the following useful link: https://tools.thermofisher.com/content/sfs/manuals/Man-XCALI-97209-Xcalibur-22-Acquisition-ManXCALI97209-D-EN.pdf