IPsec tunnel works in one direction

[Anton]

Hi everyone. Could you please help me figure out what the issue might be:
I set up an IPsec tunnel between my PC (through a Mikrotik router) and a Debian virtual machine (through an OPNsense virtual machine) in the company network. Both phases are up, and the logs indicate that everything is working fine.
However, connectivity only works in one direction: I can ping the Debian VM from my PC, but when I try to ping my PC from the Debian side, there's no connectivity. The traffic reaches the OPNsense's private (non-public) IP address, the logs show everything is okay, but the traffic doesn't go any further.