Failed to download multimedia extension

Recently I keep getting failed to download multimedia extension message after every few minutes. How could I disable it?

I do NOT want anything downloaded without my choice. When I don't use it, internet is disabled (both wifi and sim card). In Multimedia messages setting section "Download automatically" is disabled, so technically it shouldn't download anything, yet I still keep getting that message.

I tried restarting and clearing cashe as well. Didn't help. Any suggestions?