This world was saved with mod 'ava' which appears to be missing, things may not work well

I installed the mod A.V.A - Alliance of Valiant Arms Guns in a server where I had already built and when I started the server it crashed.

I tried some times to open the server and it worked once.

Then I joined the world and it inmediately crashed.

As I couldn't use this mod I uninstalled it.

When I tried to open the server then it didn't work and the register showed the message "This world was saved with mod 'ava' which appears to be missing, things may not work well".

I tried to open the server many times but couldn't make it work. Then I looked for the data of the mod ava in the files of the world and deleted it but even then it did not work at all.

What can I do to recover my world?

I attach the register: CLICK

Thank you.

And there is not a way to delete the files of the mod to be able to enter the server?