Problem db:convert from mysql / mariasql to postgressql

I tried to convert my current mariaSQL-db to a new postgres-DB with the occ db:convert tool within nextcloud 20.
At the creation of the shema I already got the error :
An exception occurred while executing ‘DROP INDEX “primary”’
What could be the issue ?

best regards


maybe this one is of any help for you as well? → Syntax Error on db:convert-type when converting any DB to ->PostgreSQL | NC 20 · Issue #24884 · nextcloud/server · GitHub