Single registration // group registration

On our site skiclub-schiltach.de group-registration is working fine, but single-registration ends up in Template errror. Using an other template ends in the "0 - count(): Argument #1 ($value) must be of type Countable|array, null given".
Can´t figure it out.
Can you help please?
Thx Klaus

Hi Klaus

Please submit a support ticket sending us super admin account of your site and link to the group registration page which is having this issue. I will check to see why the issue happens and get it sorted

Regards,

Tuan