Hi,
We kindly suggest that you first disable any search engine friendly (SEF) extensions, such as sh404SEF, if you have installed one. Then, please clear your server and browser cache and check if this resolves your issue.
If you haven't installed an SEF extension, or if disabling it doesn't help, we recommend that you raise a support ticket (https://www.acymailing.com/support/) so that we can further assist you.