@Eperjesi Zsolt Welcome to Microsoft Q&A, thank you for posting your here!!
please check if your Resource Provider enabled for AzureComputeGallery on your subscription.
It might be worth retrying in a few hours: https://learn.microsoft.com/en-us/answers/questions/600483/random-noregisteredproviderfound-error.html
If it still fails after your Resource Provider and waiting, get a support case opened: https://azure.microsoft.com/en-us/support.
Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.
Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.