You may wish to examine the network trace to see which service is returning these messages to the UI, and check their logs for further details. SAS Technical Support can help examining these, but this SAS Note describes how to look at the network trace and gather a HAR file.
I would try with an LDAP user and see if the behavior is any different given the error message is specifically calling out the sasboot user. Typically sasboot is used just to set up LDAP during initial configuration. As sasboot only exists in Viya, it does not have the ability to own server processes like compute servers which may be required by some solutions.
-- Greg Wootton | Principal Systems Technical Support Engineer