Acrobat DC append to PDF issues

[defaultg8asqdwcqvu6]

The construction group has been having issues when Appending to PDF Thru outlook 2016.

It appends the PDF but cannot create the index. It gets stuck and never completes. Theses files can be anywhere from 54000 KB to 200000 KB in size. We are using  Acrobat DC 2021.001.20145  

[eaglef50073119]

I've been having the same issues.  Sometimes when I can close Outlook, reopen and try it agian, it will work.  This is frustrating as it has only started about 4 weeks ago.