So I just updated my Version 5 to 5.10.26 and now when I go to the configuration page I see this error message:
Warning
: Use of undefined constant ACYM_ACYCHECKER_WEBSITE - assumed 'ACYM_ACYCHECKER_WEBSITE' (this will throw an Error in a future version of PHP) in
/home/endle/public_html/administrator/components/com_acymailing/views/cpanel/view.html.php
on line
599

As a result, none of the functions on the configuration page are displayed, and so I can't change anything regarding the configuration.
Note that I had to install the update manually because I was seeing an error saying there was not a license attached to my website, even though there is. Also note I have both Version 5 and 7 installed using the same license.

Is this a bug in the newest version of 5?

I can't configure after update to 5.1.26 either. If I try to configure, I get

An error has occurred.
0 Call to undefined function acym_translation()

I was able to update through Joomla Update okay. I re-installed new version manually after I saw the error. Error persists.

Using PHP 7.4.28 and 5.5.5-10.6.7-MariaDB

I also see that error message in the main area of the configuration page: 0 Call to undefined function acym_translation()

The error message I posted in the first post is showing above the main Joomla menu bar as shown in the attached screenshot:

My home page and site are working fine, but then I did not have any pop-up subscription forms as mentioned in the other thread. I just am am unable to access the configuration page in Acymailing 5.

It sounds like this latest update has more than one bug.

    Strange that ACY hasn't commented yet. This has been going all day. I just sent a support ticket, but they may be out of office.

    avkeele: Did the problem with being unable to configure anything on the configuration page also go away when you applied the fix you described in the other thread?

      Nirmalanow , no. I am still unable to configure. I did not save the old installation. ACY does not provided secured access to old install files. At least my site is back up.

        I'm on Joomla also. So the other solution has nothing to do with this configuration problem.

        It seems. Igor at ACY says, "yes, I am aware of this second issue. I am afraid that I don't have a workaround for this. I have just reported this issue to our developers, and I am afraid that we will have to wait until tomorrow for the fix."

        Just FYI.

        Fix has been provided in version 5.10.27, which our developers released today

          mihha

          I have updated to 5.10.27 and everything seems OK at first glance. Configuration seems to be working again and I see no error messages up front. But when I enable error reporting I still see:

          Warning: include_once(/home/********/public_html/components/com_acymailing/router/base.php): failed to open stream: No such file or directory in /home/********/public_html/components/com_acymailing/router.php on line 13

Warning: include_once(): Failed opening '/home/********/public_html/components/com_acymailing/router/base.php' for inclusion (include_path='.:/opt/alt/php74/usr/share/pear') in /home/********/public_html/components/com_acymailing/router.php on line 13

Warning: include_once(/home/********/public_html/components/com_acymailing/router/router.php): failed to open stream: No such file or directory in /home/********/public_html/components/com_acymailing/router.php on line 14

Warning: include_once(): Failed opening '/home/********/public_html/components/com_acymailing/router/router.php' for inclusion (include_path='.:/opt/alt/php74/usr/share/pear') in /home/********/public_html/components/com_acymailing/router.php on line 14

          Update:
          Before updating to 5.10.27 I did manually extract the router folder with no noticeable change.
          After the 5.10.27 update I tried to send emails and the system hangs at the 'Send Process' pop-up:

          After letting the pop-up sit for a while with no visible change, I closed the pop-up.
          The emails can then be verified as queued and never sent:

          Please advise.

            @EddyTippet
            Please open a support ticket using our contact for so we can take a look