Hello Mavivi.

I had same problem before on Google Chrome.  It did not like Flash Player anymore.  Alyona moderator gave me some suggestions. You can try them. Some worked for me.

1-Use a different browser.  Internet explorer (not edge) and Opera browser worked for me. 

2-Clear the browser catch every day. Many free programs can do that.

3-Wait a few minutes. Sometimes the game server is updating.

4-Check the forum. There is a help page about log in problems.

5-Send a message to Plarium support.  They can do more higher level checking or help.

Good luck!