Prerequisite for testing Docker ngrok For instance, use this ngrok for nextcloud: ngrok http --region=in 8081 Setup nextcloud instance 1. Using docker (make sure docker is installed in your machine), run the command below: docker run -d -p 8081 : 80 nextcloud You should get the latest version of nextcloud installed on your machine. Access it using URL generated by ngrok say, https://23ba1b00d3fa.in.ngrok.io . 2. Create the admin user and login to the nextcloud instance. Accessing via the ngrok url helps nextcloud set trusted domain as the same url and overwrite.cli.url automatically. 3. Disable 'Password policy' app by navigating to the 'Apps' page as admin. This helps to create user accounts s1, s2, t1 etc. 4. Now access the config/config.php file of your Nextcloud instance from the terminal using: docker exec -it <CONTAINER ID> bash Where ID is the container ID of your Nextcloud instance( you may get it from 'docker ps' command) After this open config/config.php and update it with line below (you may need to install something like vim in the container) 'overwriteprotocol' => 'https', 5. Navigate to Settings -> Security page 6. Under OAuth 2.0 clients fill up the details like: a) Name: Moodle b) Redirection URI: http://localhost/m/pg_stable_master/admin/oauth2callback.php The redirection URL is your moodle URL + admin/oauth2callback.php 7. Click on "Add" button, which would generate Client Identifier a Secret. Copy both values which are required in future steps. 8. Create a student user by navigating to 'Users' page username: s1 password: test Configure moodle instance 1. Log in to moodle as admin. 2. Navigate to Site Administration -> Server -> OAuth 2 services 3. In the "Create new service" section select Nextcloud. 4. Now fill the Client ID (copy it from step 4 of Nextcloud setup instance) 5. Fill the Client secret (copy it from step 4 of Nextcloud setup instance) 6. Fill in the "Service base URL". This has to be https address. Kindly refer to the ngrok https address which you executed in the prerequisite section. Use the https URL in "Service base URL". 7. Click on the button "Save changes" 8. Click on "System account connected" section of Nextcloud. And login as an admin account of Nextcloud. 9. Navigate to: Site administration -> Plugins -> Repositories -> Manage repositories 10. Select Nextcloud as "Enabled and visible". 11. Click on the "Settings" link right next to "Enable and visible" option. 12. Click the button "Create a repository instance". 13. Give a name to your repo: Nextcloud repo        Select issuer as Nextcloud        Select Default return types as 'External (only links stored in Moodle)'        And Save it. Steps to test Login as an admin in moodle and create a course and enroll a student in the course Add assignment activity to the course. Now login as a student and attach a file from s1 student of nextcloud instance to the assignment. Save the change. Re-edit the assignment submitted by removing the file and re-attach the file. You should not see exception.