No images created in PDF with https

We build a system to generate pdf-flyer with views pdf.
The Flyers are generated as node with a lot of image-fields, where the user can choose images from a pool.

This installation is runnig a few years on a windwos server without problems.
Now the installation was moved to an other windows server with following settings:
- Windows / Apache 2.4
- PHP 7.13 (old system 5.6)
- Drupal 7.69 (old system 7.59)
- Modul TCPDF 7.x-1.0-beta1
- Library TCPDF 6.2.13
- views pdf 7.x-1.7
- views 7.x-3.23
- jQuery Update 7.x-2.7
- Token 7.x-1.7

this modules where updated:
- faq
- filefield_paths
- l10n_update
- link
- print
- views
- webform

This is our problem:
With http the generation of the pdf works as expected and shows all images included in the node.
While calling the domain with https, the PDF is generated with background image but without the images wich are fetched as image-field in view and positioned on the background image.
In the node, the images are showed correctly - also with https.

We geht this errors in watchdog while using SSL:
- imagecreatefromjpeg(https://domain/sites/default/files/header/411/meinbild.jpg): failed to open stream: No such file or directory in TCPDF->Image() (Zeile 7033 von D:\Programme\Apache24\htdocs\sites\all\libraries\tcpdf\tcpdf.php).
- getimagesize(https://domain/sites/default/files/header/411/meinbild.jpg): failed to open stream: No such file or directory in TCPDF_IMAGES::_parsejpeg() (Zeile 171 von D:\Programme\Apache24\htdocs\sites\all\libraries\tcpdf\include\tcpdf_images.php).
- getimagesize(): Unable to find the wrapper "https" - did you forget to enable it when you configured PHP? in TCPDF_IMAGES::_parsejpeg() (Zeile 171 von D:\Programme\Apache24\htdocs\sites\all\libraries\tcpdf\include\tcpdf_images.php).

We can call the image https://domain/sites/default/files/header/411/meinbild.jpg directly in browser, also as guest.

We tried a newer version of TCPDF library, but this does not work because of missing curl-extension on this server.

Have You ever observed these errors in connection with SSL?
What else can we try to get the images in pdf well?