Thank You page does not load but shows Email logo - email not send out

sorry to have to ask here, but I read about 40 topics in the forum used extensive google and checked the documentation as well as nerving my isp.

  1. once an order is send out the thankyou page is blank but show the email.png
  2. after refresh the thankyou.tpl shows with order number, but no email has been send out
  3. the contact form works as well as the confirmation email from the backend
  4. already upgraded to a newer version of php (PHP Version 5.3.8-nmm1) but no results no error displays

and now to the strange parts, if I set up a new installation with the same template but put no smtp infos in, everything works.
tried now every possible variation, no smtp, localhost (which was supposed to work), and the smtp.mydomain.net with the unsername + 16 digit pw. the result remains the same (tested on ff, and safari)

any help, hints ideas on this one. maybe port sttings required e.g. smtp.mydomain.net:287, tls / ssl maybe mandatory?

question here is: what can I do?

check here, maybe it helps:

Read that one already earlier. As well changed the PHP version back. The thing is, all email functions work - exept of the order confirmation-, I as well called my isp and the emails do all run via the entered smtp server. They only had one error log so far stating something with “feeder or shop feeder”. The “Blank” thankyou page displays the “logo_email.png” by the way. Seen simular problems in the forum, but they seemed to have to do with other stuff. I did put as well the same installation on a different directory with the same settings, and there it does work. But prob is, the not working shop has already artcicles in it.
My last oxid shop is one year old. And with that version there were never problems so far, maybe someone working with the 4.5+ versions has a clue.

Just a guess - but maybe there are some wrong Smarty or html tags within the confirmation-email-templates or cms-pages?

and now to the strange parts, if I set up a new installation with the same template but put no smtp infos in, everything works.
tried now every possible variation, no smtp, localhost (which was supposed to work), and the smtp.mydomain.net with the unsername + 16 digit pw. the result remains the same (tested on ff, and safari)

any help, hints ideas on this one. maybe port sttings required e.g. smtp.mydomain.net:287, tls / ssl maybe mandatory?

question here is: what can I do?