Order form not displaying domain results - Redirect to product overview

[nox]

Hey all,

since the update to WHMCS 8.3 we observe the problem that when we place an order for a webhosting package (cpanel), after the domain check we are redirected back to the product overview. Thus, the order is not carried out.

 

After a thorough examination, the following problem arises in our case: https://help.whmcs.com/m/troubleshooting/l/680894-troubleshooting-order-form-issues

"Order form not displaying domain results" - We get there as described in the guide the content type "text/html" instead of "application/json". Now it gets confusing:

 

If we set the Friendly URLs in WHMCS back to Basic URLs, the problem does not persist. So it seems to be a problem with rewrite? Rewrite itself works, the existing htaccess file is recognized and read by apache2 without problems, but the environment mode inspection only recognizes the availability of Basic URLs, the other options are displayed with a red background as unavailable. Is there already somewhere in the rewrite the real cause? Before the update of WHMCS, orders worked without problems. Are there any other solutions to this problem?

Thanks in advance! :) 

Here is our htaccess: 

### BEGIN - WHMCS managed rules - DO NOT EDIT BETWEEN WHMCS MARKERS ###
<IfModule mod_rewrite.c>
RewriteEngine on

# RewriteBase is set to "/" so rules do not need updating if the
# installation directory is relocated.  It is imperative that
# there is also a RewriteCond rule later that can effectively get
# the actual value by comparison against the request URI.
# 
# If there are _any_ other RewriteBase directives in this file,
# the last entry will take precedence!
RewriteBase /

# Redirect directories to an address with slash
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.+[^/])$  $1/ [R]

# Send all remaining (routable paths) through index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# Determine and use the actual base
RewriteCond $0#%{REQUEST_URI} ([^#]*)#(.*)\1$
RewriteRule ^.*$ %2index.php [QSA,L]
</IfModule>
### END - WHMCS managed rules - DO NOT EDIT BETWEEN WHMCS MARKERS ###

 

[Joelsa]

I was having this unusual issue, that when customer check  a domain first time it shows the availability, and when domain added and continue the page goes back to previous product overview page.However this did not happen in incognito mode as well as microsft edge.It only happened in Chrome.Finally i found that  i have not put the correct secure urls with https:// in whmcs  general settings.  System Settings-> General Settings : in here make sure all the URl's are starts with https:// instead of http://. That solved my issue.