dynamoproductions

Thank you Ipstenu.

Deleting like this:

delete from wp_10_options where option_name = 'rewrite_rules' ;

or like this:

update wp_10_options set option_value = '' where option_name = 'rewrite_rules';

?

Edit: I tried the update options and the blog regenerated the key on my stage: http://blogdolci.dynamoproductions.it.

I hope the reset will never happen again if yes i will try this suggestion. The plugin that I think made the rules reset was Yoast SEO.

I deinstalled the plugin and reinstalled it in /mu-plugin/ and now seems to work: i can get the blog of the referral ID:

http://blogdolci.dynamoproductions.it/testblog5/