The Failed Ajax request or invalid JSON returned

Description of issue or problem I’m having:
When I want to make review form at stage “Create new Item”. I face this message “Failed Ajax request or invalid JSON returned”.

**Steps I took leading up to the issue:
Workflow- review- review form- Creat Review form - Edit-form Item- Create Form Item.

What I tried to resolve the issue:
Npoting to try

Application Version - e.g., OJS 3.1.2:
Version OJS 3.3.06

Additional information, such as screenshots and error log messages if applicable:
PHP error log:

[Fri Jul 30 17:32:52.449755 2021] [fcgid:warn] [pid 3843] [client 93.119.212.110:49355] mod_fcgid: stderr: #5 /home/eastern/domains/journal.eastern-healthcare.org/public_html/index.php(68): PKPApplication->execute(), referer: http://journal…index.php/ejhc/management/settings/workflow
[Fri Jul 30 17:32:52.449779 2021] [fcgid:warn] [pid 3843] [client 93.119.212.110:49355] mod_fcgid: stderr: #6 {main}, referer: http://journal…/index.php/ejhc/management/settings/workflow
[Fri Jul 30 17:32:52.449786 2021] [fcgid:warn] [pid 3843] [client 93.119.212.110:49355] mod_fcgid: stderr: thrown in /home/eastern/domains/journal.eastern-healthcare.org/public_html/lib/pkp/controllers/grid/settings/reviewForms/form/ReviewFormElementForm.inc.php on line 65, referer: http://journal…/index.php/ejhc/management/settings/workflow

Appreciate if somebody help