I don’t expect an answer here, I’m just seeing if anyone else is having this problem. I’m running Ardour 5.1.2 on a Dell computer, using Ubuntu Studio 19.10 as the OS. I can open and close two or three projects with no difficulty. However, at some point, I will get an Unable to create port error. I saw exactly the same behavior using this version of Ardour on Ubuntu Studio 18.04, running on a 2011 iMac and a 2010 MacPro. I even saw the same behavior running Ardour in Manjaro linux.
Something I thought may be an issue is that I usually run Ardour on projects that are on non-home drives, both internal and external. Has anyone else seen this behavior? Could the fact that the projects are not in the home directory be causing a problem? I do not see this behavior while running Ardour on projects in the home directory of a virtual machine.