How to get Plesk support in Openprovider?

Question
How can one receive support for either a technical or a licensing issue with Plesk software?
Answer
If the license has been purchased via Openprovider account, contact Openprovider support department having the following info at hand:
License number: PLSK.012345678 (example)
License version: 18.0.73 (example)
Server OS: AlmaLinux 10.0 (example)
Short Description of the problem in English.
Server Credentials
Submit a request via this form
NB: Our support team is available 24/7.
If you would like to have 24/7 support directly from Plesk you can activate a support subscription here.