Copy & paste of excel contents into a Confluence table doesn't work

Unfortunately I can not copy & paste content from my Excel file to a Confluence table, because all the pasted content lands in the first row only. Could you please help me?

I can not determine the same problem in my Confluence test environment, but I found a discussion about that topic in Atlassian’s Community which could be helpful for you. Please let us know, if you have further questions.

Yes, it was helpful. Thank you for that.
At the end I converted the Excel table here Markdown Tables generator - and inserted it as a markup in Confluence.