Can Not Upload a CSV file for 1 domain

Why the same newly downloaded plugin, upload the same csv file, also use the same browser, with the same host, this domain work acallresources.com. This domain knowledge-easy.com/ does not?

Here is my host asked me to contact the vendor for. You need to check with the plugin vendor and ask what are the recruitments for the plugin to use

Thank you so much for any effective help. Take care.