HTTP 500 Error
HTTP 500 errors are server generated errors indicating something has gone wrong with the request - for example when uploading a Product from FileMaker to WooCommerce or downloading Products from WooCommerce to FileMaker. The 500 error indicates that the server encountered an unexpected condition that prevented it from fulfilling the request.
The first thing to try is to use the FileMaker Script Debugger to step through the step until you have come to the Insert from URL script step that is presumably generating the error here. As soon as you have stepped past the Insert from URL script step open the Data Viewer and have a look at the $response variable to see if that contains any useful information about what is causing the error here.
As 500 errors are server errors you can also troubleshoot this is on your WordPress server by looking in the error_log file for the web server/php. The 500 error will usually generate an entry in the error_log file with some details on what is causing the 500 error, so if you can access that log file you could make a request which generates the 500 error and see the details for the corresponding entry in the log file which usually indicates what is causing the 500 error.
We've had feedback from some customers that their 500 errors were caused by issues with plugin compatibility and an updated to a particular plugin was required to resolve the issue.