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[Zend_Http_Exception] Invalid header line detected

Re: [Zend_Http_Exception] Invalid header line detected

No problem.


We've been working on this issue ourselves. We turned off litespeed and this eliminated that issue. But it isn't a fix. We are looking at upgrading litespeed as you have..


Your experience really helps us to know what to expect so we appreciate you sharing this.

Our team are working on it, and since you have shared this I will share this with them.I'll keep you updated as soon as there is any update, hopefully this week. Welcome to inbox me and give a nudge if you don't hear back and I will post back in this thread.


I had 2 more questions that would be helpful if you can assist us:

1. Did you already have linnworks integrated at the time of these issues? 

2. Did linnworks help you at all? or did they just tell you to speak to your developer?

3. What version of Magento are you using and PHP? (We are using 2.2.2)


Best of luck,

Re: [Zend_Http_Exception] Invalid header line detected

Hi Guys,


Just wanted to add myself to the thread as I am also experiencing the same issue with Linnworks integration. We don't use litemage, and the company we hired to do the Linnworks implementation did manage to configure the Linnworks initially (around Oct 2018 it was working). Later on, we attempt to go live with the implementation early Dec and then we couldn't get it working. We didn't change anything in Magento 2.


Linnwork support is involved, but I guess they are not technical enough to dig into the level of detail this issue may need.


I don’t understand Magento 2 enough to debug the issue, however; we are getting following entry in the exception log:


[2018-12-19 21:52:39] main.CRITICAL: Invalid header line detected {"exception":"[object] (Zend_Http_Exception(code: 0): Invalid header line detected at  /home/…/vendor/magento/zendframework1/library/Zend/Http/Response.php:572)"} []


We have Magento 2.2.4, with PHP 7.0. I am now considering to upgrade it to 2.2.7 in case there are bug fixes for this issue.


Piyush Srivastava

Re: [Zend_Http_Exception] Invalid header line detected



Thanks for sharing. We still have this problem there. Just to let you know that we are on magento 2.2.6. Please let us know if you have any luck with 2.2.7

Re: [Zend_Http_Exception] Invalid header line detected

Hi There We have managed to fix the issue. I don’t prefer this fix but with pressing time pressure I have accepted the fix. The fix incorporated the fix mentioned in and fix suggested by Orson In


Apparently, Magento is aware of this issue and the fix will be released in 2.3.1. Let me know if you need any further assistance with this.


Hope it Helps

Piyush Srivastava



Just a note to the earlier question, Linnwork support was ok, and they tried to help as much as they can. You need a well informed technical person to investigate this kind of issue and often support guys are not that technical. The real disappointment was from the company( we hired. Very hands off, tunnel view and no technical expertise. Even for a very small issue, they lean back to Linnworks. Linnworks referred them and now I am wondering why they refer to such a company. Not hiring them for future projects.


Re: [Zend_Http_Exception] Invalid header line detected

see this solution, I'm trying


scroll to the end "What to do if I see "Invalid header line detected" error message when placing an order with Affirm?
used that fix
the error in the admin disappeared and it proceeds with the integration (I'm waiting for my client to do this)

Re: [Zend_Http_Exception] Invalid header line detected

I can confirm also that the above solution did work, Linnworks is connecting again :-)

Re: [Zend_Http_Exception] Invalid header line detected

Maybe this workaround would help you.

Re: [Zend_Http_Exception] Invalid header line detected

I stucked with the same problems. As I see, reasons can be different. 
In my case, it was empty char at the end string of base_url. 

I described how to debug it and descide where is the problem here: