If you can't upgrade to the latest version of WinEdt, you can instead open a local copy of the file Adobe.edt from the Options menu -> Options Interface dialog -> Advanced Configuration -> PDF Macros -> Adobe Blues.
In this file, replace the line at the very end of it
// Assign(!"Acro-DDE_Service",!"AcroviewR11"); with the following
Assign(!"Acro-DDE_Service",!"AcroviewA17"); then save the file and restart WinEdt.
Addendum: Name of the DDE service for different versions of Adobe DC
Adobe Reader DC 2015: AcroviewR15 Acrobat DC Pro 2015: AcroviewA15 Adobe Reader DC 2017: AcroviewR17 Acrobat DC Pro 2017: AcroviewA17 Adobe Reader DC 2018: AcroviewR18 Acrobat DC Pro 2018: AcroviewA18
Unless Adobe changes its naming convention, for future versions it suffices to change the last two digits according to the year version.