That sort of error generally means that some other program current using the ASIO driver. Could that be the case? How about running AmpliTube as a plug-in in a Digital Audio Workstation ("DAW")?
As this is primarily a user to user forum, someone-else may chime in [#]. Meanwhile, the best thing to do is continue to work with Support or raise a
Support Ticket, here for some one to one investigation and help (US (East Coast) Business hours, generally). Response time is usually within 2 working days, but in the current circumstances please allow some more time.
[#] But please remember that the same symptoms do not necessarily mean the same problem.
And, to help others who run into a similar problem, please let us know what you did to resolve the problem.