fix: 504 Gateway Timeout Errors (appsmithorg#1845)

## Checklist
I have:
- [x] run the content through Grammarly
- [ ] linked to sample apps when relevant
- [ ] added the meta description for each page in the PR
- [ ] minimized the callouts and added only when necessary
- [ ] added the `queryString` parameter to the Tabs (if used)
- [ ] masked PII in images. For example, login credentials, account
details, and more
- [ ] added images only when necessary
- [ ] deleted the images that are no longer used for the updated pages
in the PR
- [ ] followed the image file naming convention while renaming or adding
new images. (Use lowercase letters, dashes between words, and be as
descriptive as possible)
- [ ] used the `<figure/>` tag instead of a markdown representation for
images
- [ ] added the `<figcaption/>` tag to add a caption to the image
- [ ] added the `alt` attribute in the `<img/>` tag
- [ ] verified and updated the cross-references or created redirect
rules for the changed or removed content
- [ ] reviewed and applied the style changes for UI formatting. For
example, Bold the UI elements(Buttons on screen) used in the doc.

website/docs/help-and-support/troubleshooting-guide/action-errors/README.md

@@ -33,6 +33,20 @@ You could resolve the error response by doing one of the following:
 - [Timeout Configuration](/connect-data/reference/query-settings): The Appsmith server has a default internal timeout of 60 seconds. If your queries take longer than this, you can set a value greater than 60 seconds. For self-hosted instances, you can set the `APPSMITH_SERVER_TIMEOUT` environment variable to a value greater than 60 seconds. For example, if you want a timeout of 80 seconds, use- `APPSMITH_SERVER_TIMEOUT=80`.
 
 
+### 504 gateway timeout
+
+#### Error message
+
+<Message
+ messageContainerClassName="error"
+messageContent="504 Gateway Timeout"></Message>
+
+#### Solution
+
+The challenge lies in the fact that when Appsmith calls an upstream API, it times out after 60 seconds, whereas the necessary timeout duration is 300 seconds. Furthermore, the default timeout for Nginx, the web server employed by Appsmith, is set at 60 seconds. To resolve this issue, one plausible approach is to extend the Nginx timeout to 300 seconds.
+
+However, Appsmith is constrained by the default 60-second timeout imposed by Nginx. While the Appsmith team is actively working on this constraint, a temporary solution involves optimizing the upstream API to deliver a response within the 60-second timeframe.
+
 
 ### Configuration error