We have noticed this happening due to the weekend Hotfix which is planned for this weekend.
If it is not something urgent, please check once again after the weekend.
If it is very important, please create an incident so we can help you further.
Just to provide some references:
a) Half-yearly downtime window for upgrades / weekly maintenance window for software patching: https://www.sap.com/documents/2017/01/867629d8-a27c-0010-82c7-eda71af511fa.html
b) Details for hotfix collection blue-green deployment in quality systems: https://launchpad.support.sap.com/#/notes/3042314
c) Details for hotfix collection blue-green deployment in production systems: https://launchpad.support.sap.com/#/notes/3024158
If you see restrictions which are not covered by these documents, it would be good to open a customer incident to address the issue.
Thanks & regards,