Issue Summary

Currently in the page editor's code there is a 20 seconds timeout configured for page preview, so in case of large pages, the preview fails after 20 seconds to avoid performance issues, this timeout is set inside core.js.map and stats.json inside com.atlassian.confluence.plugins.confluence-editor-plugin-xx.x.xx.jar file

#### In core.js.map
.ajax({\n                type: 'POST',\n                url: CONTEXT_PATH + '/pages/rendercontent.action',\n                data: queryParams,\n                success: replysetPreviewArea,\n                timeout: 20000,\n                error: () => {\n                    trigger('rte-preview-action-selected'); 


#### In stats.json

AJS.safe.ajax({\n      type: 'POST',\n      url: CONTEXT_PATH + '/pages/rendercontent.action',\n      data: queryParams,\n      success: replysetPreviewArea,\n      timeout: 20000,\n

Steps to Reproduce

1. Create a page with a large amount of Jira issues and content
2. Before saving the page, click preview, an error is thrown " Unable to Communicate with Server"

Increasing the page timeout from General Configuration > Security Configuration > Page Timeout, doesn't affect the preview timeout.

Expected Results

The preview timeout value should be configurable

Actual Results

The preview timeout value is not configurable and is set in the editor to 20 seconds

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available