Plugin not working at all with Wordpress 5.8.3 ? api_key and other variables cannot be saved.

[codeandflow]

I have installed and activated the plugin.
Via Settings -> Mandrill I cannot enter and save an api_key, there is a forward to the home page and no changes are there.

I was checking the code and hardcoding the api_key via wpMandrill.class.php -> getAPIKey(),
then, I was coming to a next site to customize different fields. But here, the same problem does occur.
I cannot set anything and I'm forwarded to the home page without any data base change.
This seems to be a severe issue, because the plugin cannot be used at all.
Please check & provide support/a fix.
Many thanks in advance!

[MillerMedia]

Thanks for sending this issue over and sorry for the delay. We are working on resolving now!

[MillerMedia]

Hi @codeandflow , we have just tested the plugin and it seems to save the variables fine. When you say it forwards to the homepage, do you mean of the admin dashboard or the root of the site? Also, are you on a single site or multisite?

[crstauf]

I recall having a similar issue awhile back, and I think it had something to do with object cache. 🤷‍♂️

[MillerMedia]

Ok, I will keep this issue open and if there are any additional details that can be found to recreate this, let's add them here. It's hard to tell if it is a plugin issue or a conflict with another plugin.