Hello max3o1,

Personal e-mail scanner is the right plugin for Mozilla Thunderbird.

If you are using other than standard ports(SMTP 25, POP 110) for sending/receiving your email please check FAQ 3014.

You can also check E-mail client settings sticky post.

If you are sure that your settings are correct please provide us with more information and with e-mail configuration screenshots.

As it is not possible to attach files to cnet posts, please use some online imagehost (e.g. imgur).

Thank you