Zimbra Forums

Subject: Experiencing HTTP ERROR 504 - Need Assistance

Greetings,

I hope you're all doing well. I've recently encountered a recurring issue when accessing our Zimbra Collaboration Suite (ZCS) server, and I'm seeking some guidance on how to resolve it.

Problem Description:

When trying to access our ZCS server, I'm consistently encountering the following error message:

HTTP ERROR 504
Problem accessing ZCS upstream server. Reason: Cannot connect to the ZCS upstream server. Connection timeout.
Possible reasons:
- Upstream server is blocked by a firewall.
- Upstream server is failing to send back the response in time.
- Upstream server is down.
Please contact your ZCS administrator to fix the problem.
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Possible Causes:
Based on the error message, it appears that there are several potential causes for this issue, such as firewall blocking, server response delays, or server downtime.

Request for Assistance:
I'm not the administrator of our ZCS server, so I'm reaching out to this community for suggestions on how to troubleshoot and potentially resolve this issue. If anyone has experienced a similar problem or has expertise in Zimbra Collaboration Suite, I would greatly appreciate your insights and recommendations.

Steps Taken So Far:
I've tried clearing my browser cache and cookies, but the issue persists. It seems to be affecting multiple users within our organization.

Next Steps:
I plan to contact our ZCS administrator, but I would like to gather as much information as possible to assist them in diagnosing and fixing the problem.

Any advice, troubleshooting steps, or insights you can provide would be incredibly helpful. Thank you in advance for your assistance!

Best regards,

This is an issue that is local to you server.
You should ask your sysadmin about it.

Have you solve this problem?

We are facing the same issue randomly with 2 users out of 650.
Thank you

We have been getting this too; it looks like it's to do with slow MySQL response.... Sometimes if the mailboxes get too big and these users have massive number of folders the SQL statements are really long and when a number of users all access the same time it causes this.

You can look at optimising MySQL; e.g. adding more RAM.