This will walk you through how to fix the issue where the integration stops working.
First, go to where the .DLL files are saved: this should be something like C:\User\"userName"\AppData\Roaming\Microsoft\AddIns.
If you don't have the .DLL files, they are attached at the bottom of this article; make sure you grab the right ones for your Excel. You will need to put them in this location:
Rename the swiftxl9.dll to have a space before the 9, so it is like this: swiftxl 9.dll.
Now register the .DLLs using cmd.
Launch cmd in Admin mode and enter:
Press Enter and run this command:
Now run this command:
regsvr32 "swiftxl 9.dll"
That should resolve the issue.