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Google Optimize Preview Errors

[ Edited ]
Visitor ✭ ✭ ✭
# 1
Visitor ✭ ✭ ✭

After successfully using Google Optimize on our company site for many months, it's recently started showing errors when I try to preview a new URL Redirect test.


Preview 1 is showing the "Invalid input" (seen below) and 

Preview 2 is going to a page that does not exist. 

Invalid input. Please press your browser's back button and re-attempt your submission.
Please double-check that the characters you entered are normal A-Z or 0-9 alphanumeric letters or numbers. If you are using any special symbols in your submission, please remove them, and then re-submit your request.

Example of special characters would be the following: !@#$%^&*-(),+={}?:"

If you continue to experience problems, please contact customer service with the following information:
Time of error: 8/31/2017 4:17:41 AM CST
Field Name: utm_preview
Web Page: /Default.asp


I've tried rebuilding the test, flushing the cache on the site, changing the target URL - nothing has worked.

It seems that a similar Previewing Error is occurring in other accounts we're using to test different sites.

Any advice is appreciated!

1 Expert replyverified_user

Google Optimize Preview Errors

Google Employee
# 2
Google Employee

Can you provide the URL of the pages that you try to redirect to? Optimize experiments add utm_preview or utm_expid query parameters to the destination URLs and it looks like that your website is trying to parse those query parameters.

Google Optimize Preview Errors

Visitor ✭ ✭ ✭
# 3
Visitor ✭ ✭ ✭

Yes, they are
(this one's preview redirects to a blank page)

thanks in advance.

Google Optimize Preview Errors

Visitor ✭ ✭ ✭
# 4
Visitor ✭ ✭ ✭

Hello, do you have any more advice regarding this issue?

Please advise,

Google Optimize Preview Errors

Google Employee
# 5
Google Employee

Sorry for the delayed response.


Optimize redirect experiments add some new query parameters to the URL after redirection to track the experiments. The query parameters used are:

- utm_preview for preview experiment and utm_expid for running experiment

- utm_referrer to track the referrer to the original page.


It looks like that the home page of your website has some interaction with the utm_preview query parameter that Optimize uses when generating preview URL. The URL:$

generates the "Invalid input" page, but URL$

seems to work fine.


The article page seems to have some interaction with any arbitrary query parameter that has a value that ends with '.html':

generates an "Article not found" page.


In order for the Optimize redirect experiments to work, website should ignore additional query parameters added to the URL that it doesn't handle.