Earlier versions of PDF2XL are dependent upon Excel for an Excel file conversion. When running batch conversion, particularly with a high volume of documents, you may encounter the conversion process freezing up and returning a "Server is Busy" error.
Regrettably, as this is an Excel issue, it's not something within our ability to correct.
There are two options to solve this problem:
Convert fewer documents at a time.
Purchase a subscription plan. With our new product line, we switched to LibXL so that these kinds of Excel issues would no longer occur. (Note that these plans are a new product line, and there is no upgrade from v6.5 or lower to this one)