Hi, The Newsletter plugin runs on a single site. It was first installed on a different domain’s server (same Internet Service Provider) under normal HTTP protocol.
I migrated the site on to another server (same ISP) and the domain changed as well. After the migration HTTP changed to HTTPS. Newsletter worked well on the previous installation/server (I just tested during the site creation process though). The site never worked as was intended for some other reason.
So, back to the point. When I make a request (submit) with the widget I get this page: “Bad Request – Invalid URL HTTP Error 400. The request URL is invalid” error message.
Despite of the error, the request arrives at the input email account. Using the confirmation link of the email’s content the same error message page appears instead of the thank you for the registration /confirmation form of the site.
Despite the error the subscribe confirmaton letter arrives at the given email account. There are several links in this email too. All triggers the same error, moreover in WP dashboard/Newsletter/subscriber list/data page click results the same.
I hope you can help me, bring me light about the reason of the error and would suggest the solution.
Note. I deleted once the plugin, manually from the server as well and reinstalled (remembered the previous setup data though). Nothing has changed.