Upon further testing I have found that it is related to a specific custom field. I have a dropdown for T-Shirts with values "None|1|2|3|4|5|6|7|8|9|10", it is a fee field with the following fees "0|20|40|60|80|100|120|140|160|180|200"
I have ten conditional fields for Shirt Sizes. All of them are dropdowns with values "Small|Medium|Large|XL|2XL|3XL (+$5)|4XL (+$5)", they are also fee fields with values "0|0|0|0|0|5|5"
They are set up so that if the tshirt drop down value is one then one shirt size dropdown appears, if the dropdown value is two then two shirt size dropdowns appear, and so on...
All of that works and the fee updates as expected.
However, with that field published and used in the event I get the "blank" confirmation page. With that field unpublished the confirmation page comes up as normal.
Through a process of trial and error I seem to have identified the issue and a work around to my problem. Not elegant but at least the registration process proceeds to confirmation page.
When three of my fields that have drop down menus are active for an event the registration won't progress to the confirmation page. However, when I changed the drop down to a radio button, without changing anything else in the field, the registration progresses successfully. Strangely I have other drop down fields that cause no problem so it is not a blanket issue. So lots of trial and many errors to identify which fields were the problem.
Thinking it might be an error with how the DTReg update saved these particular fields I tried to create a new field using the settings I wanted but same problem appeared.
So for some reason when I updated to 2.7.1d three fields decided they wouldn't work with drop down menus but will with radio buttons.
Not sure what has caused this to occur as in previous versions of DT Reg these fields worked fine with drop downs.
I'll confirm that if I change my troubled dropdown to a radio it works. However, if I cause any of my conditional dropdowns to appear then it fails again. So the issue is definately related to dropdown fields.
If you can use radios instead you may be ok. However, for me radios are far to unsightly given the number of choices I have in my dropdowns.
Not sure if this is the place, but could be the trouble for some of you.... It's a glitch caused through bad practice on the web mgr side which maybe could be prevented with a bit of toughening to the core component maybe (or maybe we just have to stay aware of it!)...
I have found that if you go to the first page of a Registration and copy the generated link of that page - and then use that elsewhere as an intended link to the frontpage, then when you follow that link and try to register you'll end up with a blank 'Confirm Details' page....
(The correct link to take is the one that shows on the Event Registration page - which is actually shorter than the one you get when you're actually on Page 1 of a registration!
I have not use the copying of links yet (not to that point), I've been going in through the event registration link from the list of events. However, if I go straight through the registration process without changing the value of the dropdown it works. If I change the value of the dropdown or go back and thus change the URL it fails.
I thought this was related to custom fields as well and did the trial and error thing. I could not find anything consistent. If I unpublished the custom field, tried it again, it would work for me. If I asked someone else to try, it would not work for them. I could not figure it out so we went back to 2.6.