Hello,
I'm using a DB version 19c with APEX 20.2.0.00.20 installed successful on an always free autonomous database with server in Frankfurt/Germany.
For MLE testing I installed a 21c in parallel on the same server. APEX is running (20.2.0.00.20). First I copied my working APEX app from the 19c to the 21c database, but I run in an error while the "Rest Data Source" wasn't working.
To check that I installed the "Sample Rest Services" application from the gallery and run the "test service endpoints". Unfortunately I get the error "Other Error: ORA-28759: failure to open file". The same sample application is running well on the same server with DB 19c.
Also if I create a new "Rest Data Source" from scratch I get the following error in the wizard.
Any idea?