Execution engines fails to start after upgrading to 18.4

Hi All,

We are trying to upgrade appian from 18.2 to 18.4.

Followed the steps mentioned in update guide, when we try to start appian services after migrating the old data, all execution engines failed to start. Engines are in either "STARTING" or "REPLAYING" state.

Any suggestion to troubleshoot this issue?

Thanks in advance,

Nishanth