"Unable to test" message


New Member
Hello team, I'm a new user of Email Verifier. Nice to be here.
I remember I tried the product some time ago and it worked pretty well. However now I bought the license, installed in the office and all I got is the "Unable to test" message for all the emails I try. Even though those I know there are correct.
Could you give me a clue about what to check first in Settings?