I have a site which I can used the SharePoint Designer to edit it (add subsite, edit texts and documents...). However, started last week. I no longer been able to use Designer to access that site (other sites are fine. both SharePoint 2013 or SharePoint 2016. http or https). This is the only SharePoint site in that server (Windows 2016, SQL 2017 and SharePoint 2016). It seem cannot find the services? It was interesting that you can connect to the site with Designer in the first time (it took about 5 minutes, other sites only took about 5 seconds). But I got the following error started second time:

and in SharePoint Designer, the following messages for above 20 minutes, then I got the above error. I have ask the system administrators, they seems do not know what is going on. I wish if someone have this issue and know the solution, please help me out. Many thanks
