When I try to create a page from a list of available templates instead of the default blank by clicking on the "..." button, the window that appears is always blank and has a spin wheel that never stops.

When I look at the logs, I catch the following error / message:
2018-09-04 16:16:02,832 WARN [http-nio-8090-exec-9] [confluence.impl.hibernate.ConfluenceHibernateTransactionManager] doRollback Performing rollback. Transactions:
->[PluginReadWriteTx]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT (Session #1687516122)
-- referer: https://doc.truonix.io/display/TRQ/MVP+Phase+II+-+Assessment+Setup | url: /rest/create-dialog/1.0/blueprints/web-items | traceId: 5a0aa0d21abd8427 | userName: yanfosec
I cleared out cached plugins and rebooted the server (https://confluence.atlassian.com/confkb/how-to-clear-confluence-plugins-cache-297664846.html)
When I manually run the REST query, I get the following error:
{"errorCode":400,"errorType":"PARAMETER:MISSING","errorData":"spaceKey","errorMessage":"Missing 'spaceKey' parameter"}Please, let me know what else I can try to fix this issue.
Yan