Atlassian applications allow the use of reverse-proxies within our products, however Atlassian Support does not provide assistance for configuring them. Consequently, Atlassian can not guarantee providing any support for them.
If assistance with configuration is required, please raise a question on Atlassian Community.
In case you are unable to troubleshoot and fix the problem by yourself, please create a support ticket at support.atlassian.com and attach the following information to the ticket:
Copy and save the contents of the 'Diagnostics' tab as a text file.
Screenshots of the Application Links configuration.
A Support ZIP.