PLEASE HELP // not showing the tv show poster

Hello

I am having a problem with the wonderful program Televzr

When I add a series to my library, the program recognizes it but it does not display its own poster :'(

As you can see in the image below, the program recognize these series, but it did not show the poster for some of them.

tried to remove them from the library and re-add them again and again but without result
Just for reference: I have no problem with the Internet

PLEASE HELP !!

PLEASE HELP !!

PLEASE HELP !!

PLEASE HELP !!