Hello,
The first problem: for the current environment, first check whether the direct connection between the corresponding devices is accessible, and then check whether the route is accessible. If there is a firewall, check whether the firewall releases the corresponding security policy.
The second problem: 9312 and 5310 of an indirect line, such as the firewall is three layers, that generally will not have a loop, such as a firewall is two layers, then there may be a loop.
Hope to help you!