Chat not working. Server error occurred: Not Found

Hi,
I bought Wise Chat pro just yesterday and am having problems with it. I have uploaded it to my website, and included it in one of my buddypress groups.

Upon testing it out, I found the following error in the chat box: Server error occurred: Not Found

I typed a message and pressed return. Nothing happened. But when I refreshed the page the message was there and under it the same notice: Server error occurred: Not Found

Since the error seemed to be with the server I contacted the technical support at my server provider. They looked into the issue and explained the following:

The error 404 seems to be owing to the following:
https://h2english.com/wp-content/plugins/wise-chat-pro/src/endpoints/?action=wise_chat_messages_endpoint&channelId=1&lastId=12&checksum=On8PElvN4KhfH7
This is the link that the chat plugin uses to work and the server can’t open it for some reason. The server thinks that it doesn’t exist and for some reason sends back a 404 Not Found.

In addition to this the technical support explained that they have not been able to find any errors in the server logs.

I would be really grateful if you could help with this issue.
Thanks very much in advance for your help.

https://www.ads-software.com/plugins/wise-chat/