Bertil Friman

More: I found out that it is easy to disable U-block for a particular site. Click the ub-icon. A square with a big power on symbol i shown. Click the “power on” symbol and U-block will remember to turn off the add block on this particular site.

Thanks for fast response. I think I have found the cause.

First, I tested on Firefox on another computer. And MailPoet worked!

Then I considered reinstalling firefox on the computer where mailpoet did not work. In the tips it said that one should also test with all addons disabled. So I looked at the addons. There was one called U-block, an add-blocker. So I thought maybe that U-block thinks that Mailpoet windows are advertisments. When I turned off U-block, Mailpoet worked as usual again!

Thanks for pushing me in the right direction.

Best regards

Bertil Friman