I had the same problem with the upload, I have used this plug in for a long time now with no issues. That is until this last update. I contacted ServMask using the help from the back end of my site.
My problem was solved within 12 hours.
Here is the solution that was given to me that worked.
Could you download the File Extension from this page: https://import.wp-migration.com.
Here is what I think happens, this added extension chucks up the file upload so there is no stalls. I think we are experiencing stalls with uploading the file.
I suggest installing this extension – it is made by the same people and worked for me.
I wish you luck. I have found that the developers of this plugin have been GREAT to me.
