For self-hosted JIRA instances it may happen that when creating an application link in JIRA for Jirio, Jirio still won’t be able to connect to JIRA and will fail with the following message.
The reason is that JIRA verifies timestamps for all incoming requests that come from 3rd party integrations, including Jirio JIRA Slack app. This error message means that the time on the JIRA server is a off and needs to be synced with NTP server.
Syncing time is fairly easy to do and can be achieved with the following techniques on Ubuntu server https://help.ubuntu.com/lts/serverguide/NTP.html
Once this error is gone, Jirio should be able to connect to JIRA without errors.