I expect getting error message clearly identifying the cause of failure, but not silent terminal session disconnection...What you expect?
> /interface/detect-internet/ print
detect-interface-list: WAN
lan-interface-list: none
wan-interface-list: none
internet-interface-list: none
Didn't help as expected, due to to completely unrelated to problem described.Try clearing the cache before you login using the Tools->Clear Cache option.
/ip routeprint. I don't want to create anything, just to filter out unreachable routes in PRINT command.You can create a bridge "unreachable" without ports and addresses, then route the traffic there. Now create a firewall rule to match packets to that interface and reject.