Invalid problem. Please go back and try another one.

“Invalid problem” means something wrong with the problem storage.

Check if “math_quiz_problems” table exists in your database, and see if new problems getting added to database when you visit “/index.php?math_quiz_ajax=get_problem”

The table does not exist

https://www.dropbox.com/s/fcu6z8sz4vborey/tabellen%20%281%29.png?dl=0
https://www.dropbox.com/s/cmk5225przwhloi/tabellen%20%282%29.png?dl=0

Disable plugin and delete plugin setting from database, and re-enable it to see if table was created.

DELETE FROM wp_blog_options WHERE option_name = 'math-quiz-setting';

Plugin disabled , settings deleted

https://www.dropbox.com/s/liwrr22f4h85r4u/gel%C3%B6scht.png?dl=0

table is not created

https://www.dropbox.com/s/u7mieg5dz3w8ud7/mathquiz%20%282%29.jpg?dl=0

Table is not created after enabling plugin again.

Sorry, I tried it on my website, but everything works, including recreating the table.

Maybe there’s some conflict with other plugins.

Thank you for your patience: I think not that’s a conflict with other plugins
Health Check Troubleshooting Mode says everything is ok. So I tried it manually:

I deactivated all plugins, switched to theme 2019,

DELETE FROM kas_wp_options WHERE option_name = ‘math-quiz-setting’

and activated the one and only plugin MathQuiz
https://www.dropbox.com/s/4irvxkqgnwlf87d/Screenshot%202019-09-25%2022.09.57.png?dl=0

settings saved : https://www.dropbox.com/s/o11br1enij52fib/Screenshot%202019-09-25%2022.12.14.png?dl=0

and no MathQuiz-Captcha visible …

Then I switched back to theme 2012 child

MathQuiz Captcha is visible

https://www.dropbox.com/s/le03hcmv1dk9w2l/Screenshot%202019-09-25%2022.26.00.png?dl=0

but gives the same message as always:
https://www.dropbox.com/s/79cc779baehsv5x/Screenshot%202019-09-25%2022.26.18.png?dl=0

And in all cases the table was not created …

Any other ideas? Would it help to create the table in the database?

Hi
I’ve got the same problem.
On the ?math_quiz_ajax=get_problem page the refresh quiz button doesn’t work either.
No math-quiz database created.

I started wondering if your database user had enough privilege to create table?