HTTP Loopback - where the server couldn't access the site which is hosted in the same server

[girish]

@dsp76 first step to debug is to open a web terminal of the lamp app and see if curl https://other.instance works .

Usually, this should work automatically and apps can reach each other by domain name.

[dsp76]

Yes, the curl from web terminal worked. The diagnostics from infinite says something else - see http loopbacks:

Based on that discussion, curl / wget seems not the diagnosis for this issue:
https://serverfault.com/questions/420897/how-to-enable-http-loopback-connections

I have no idea, how the vservers are set in cloudron. Maybe there needs to be something additionally added to make it work so servers on the same instance reach each other?

[dsp76]

Actually another WordPress Plugin also means, that the Rest API is not activated.
I know its working from using Insomnia / Postman, but the plugin within the WordPress instance can't reach the API of the same instance.

[girish]

@dsp76 mm, but curl working means that http lookback is indeed working though. Let me see if I can reproduce this. I guess I just install the plugin and the error shows up in the diagnostics?

[girish]

I have been searching for the last 5 minutes but where is the diagnostics screen in IWP?

[girish]

Unfortunately, I couldn't find it. Let me know where this diagnostics screen is.

Also, are you using Cloudflare or some other proxy?

[dsp76]

That was the response of WPML:

Located here: /wp-admin/admin.php?page=sitepress-multilingual-cms%2Fmenu%2Fsupport.php
Meanwhile, it shows REST API supported. I wish I had saved a screenshot... it makes me look like a fool

No cloudfare etc., all is directly connected.

[dsp76]

Actually, the diagnosis came from the IWP server component. It still says:

[girish]

@dsp76 said in HTTP Loopback - where the server couldn't access the site which is hosted in the same server:

Located here: /wp-admin/admin.php?page=sitepress-multilingual-cms%2Fmenu%2Fsupport.php

Ah, looks like this from some other plugin and not IWP (per the url) ?

[dsp76]

Exactly, I had trouble with two plugins at the same time:

1. WPML (sitepress-mulilingual-cms)
2. InfiniteWP

For WPML - not sure if that was related to HTTP Loopback - the API is again reachable.
InfiniteWP still complains about the loopback issue.

I will give it a try with another WP Instance later today. Will report back.

[girish]

Atleast, InfiniteWP works fine for me in WordPress Developer . Can you try in that?

I could not install it in Managed WP. It wants to install it in the iwp subdirectory. This is not allowed in the managed WP package.

[dsp76]

Hi @girish - we again run in this issue, while we choose a workaround in January.
We can't connect from infiniteWP Panel (installed in this instance) to a LAMP instance.

We came back to the loopback issue, which was also mentioned in the IWP diagnostics:
https://support.infinitewp.com/support/solutions/articles/195234-error-while-adding-a-wordpress-site-to-the-infinitewp-admin-panel

Should we be able to connect from one Cloudron App to another? We even tried with the Instance "local" IP address, but had no luck.

[girish]

@dsp76 yes, apps can connect to each other with the domain name. Can you see if you can curl https://lamp.domain.com from the Web Terminal of the infiniteWP app instance?

[dsp76]

Right, that seems to work. Looks like something within infiniteWP is the issue? I will contact their support. I wonder why the loopback check within infiniteWP fails.

[girish]

@dsp76 yes, I am happy to debug the issue with them, if they can give us hints on how to debug the issue on their side with cURL or equivalent.

[chriskloss]

Response from IWP: https://support.infinitewp.com/support/tickets/497259

"I had a developer look into this issue, and he confirmed that our code was having trouble detecting the HTTP Loopback request.
So, I kindly request you ignore the HTTP loopback status on your IWP admin panel."