Undefined index: uidnext When Using Mail App

Steps to reproduce

Install Mail App
Add multiple IMAP Internet Accounts
Browse mail; error pops up in log

Expected behaviour

The log should be free of errors

Actual behaviour

I get the following error in the log: Undefined index: uidnext at /var/www/nextcloud/apps/mail/lib/Account.php#701

Server configuration

Operating system: Ubuntu 16.04 Server

Web server: Server version: Apache/2.4.18 (Ubuntu) Server built: 2017-07-27T14:34:01

Database: Your MariaDB connection id is 1076 Server version: 10.0.31-MariaDB-0ubuntu0.16.04.2 Ubuntu 16.04

PHP version: PHP 7.0.18-0ubuntu0.16.04.1 (cli) ( NTS ) Copyright (c) 1997-2017 The PHP Group Zend Engine v3.0.0, Copyright (c) 1998-2017 Zend Technologies with Zend OPcache v7.0.18-0ubuntu0.16.04.1, Copyright (c) 1999-2017, by Zend Technologies Nextcloud version: (see Nextcloud admin page) 12 RC5 Updated from an older Nextcloud/ownCloud or fresh install: 12 stable --> RC4 --> RC5 Where did you install Nextcloud from: Git

Signing status:

Signing status

``` Login as admin user into your Nextcloud and access http://example.com/index.php/settings/integrity/failed paste the results here. ``` No errors have been found. **List of activated apps:** root@cloud:/var/www/nextcloud# sudo -u www-data php occ app:list Enabled: - activity: 2.5.2 - admin_audit: 1.2.0 - audioplayer: 2.0.2 - bookmarks: 0.10.1 - bruteforcesettings: 1.0.2 - calendar: 1.5.3 - checksum: 0.3.5 - comments: 1.2.0 - contacts: 1.5.3 - dav: 1.3.0 - deck: 0.2.1 - drawio: 0.8.8 - federatedfilesharing: 1.2.0 - federation: 1.2.0 - files: 1.7.2 - files_accesscontrol: 1.2.4 - files_downloadactivity: 1.1.1 - files_pdfviewer: 1.1.1 - files_sharing: 1.4.0 - files_texteditor: 2.4.1 - files_trashbin: 1.2.0 - files_versions: 1.5.0 - files_videoplayer: 1.1.0 - firstrunwizard: 2.1 - gallery: 17.0.0 - groupfolders: 1.1.0 - logreader: 2.0.0 - lookup_server_connector: 1.0.0 - mail: 0.6.5 - nextant: 1.0.8 - nextcloud_announcements: 1.1 - notes: 2.3.1 - notifications: 2.0.0 - oauth2: 1.0.5 - onlyoffice: 1.1.3 - password_policy: 1.2.2 - provisioning_api: 1.2.0 - serverinfo: 1.2.0 - sharebymail: 1.2.0 - socialsharing_email: 1.0.1 - socialsharing_facebook: 1.0.1 - socialsharing_googleplus: 1.0.1 - spreed: 2.0.1 - survey_client: 1.0.0 - systemtags: 1.2.0 - tasks: 0.9.5 - theming: 1.3.0 - twofactor_backupcodes: 1.1.1 - twofactor_totp: 1.3.0 - updatenotification: 1.2.0 - workflowengine: 1.2.0 Disabled: - encryption - files_external - registration - user_external - user_ldap `` **Nextcloud configuration:** { "system": { "instanceid": "ocbihr9vsn1t", "passwordsalt": "***REMOVED SENSITIVE VALUE***", "secret": "***REMOVED SENSITIVE VALUE***", "trusted_domains": [ "cloud.example.com", "cloud.example.me" ], "datadirectory": "\/cloud\/mount", "dbtype": "mysql", "version": "12.0.1.4", "dbname": "nextcloud", "dbhost": "localhost:5432", "dbport": "", "dbtableprefix": "oc_", "dbuser": "***REMOVED SENSITIVE VALUE***", "dbpassword": "***REMOVED SENSITIVE VALUE***", "installed": true, "memcache.local": "\\OC\\Memcache\\APCu", "memcache.locking": "\\OC\\Memcache\\Redis", "filelocking.enabled": "true", "redis": { "host": "\/var\/run\/redis\/redis.sock", "port": 0, "timeout": 0 }, "maintenance": false, "mail_smtpmode": "php", "mail_smtpauthtype": "LOGIN", "mail_from_address": "webmaster", "mail_domain": "example.com", "overwrite.cli.url": "https:\/\/cloud.example.com", "overwriteprotocol": "https", "updater.release.channel": "beta", "loglevel": 3, "theme": "", "htaccess.RewriteBase": "\/", "updater.secret": "***REMOVED SENSITIVE VALUE***" } } ``` If you have access to your command line run e.g.: sudo -u www-data php occ config:list system from within your Nextcloud installation folder or Insert your config.php content here. Make sure to remove all sensitive content such as passwords. (e.g. database password, passwordsalt, secret, smtp password, …) ```

Are you using external storage, if yes which one: local/smb/sftp/... No

Are you using encryption: yes/no Yes, LUKS mounted container

Are you using an external user-backend, if yes which one: LDAP/ActiveDirectory/Webdav/... No

Client configuration

Any

Operating system: Windows 10/7

Logs

Web server error log

Undefined index: uidvalidity at /var/www/nextcloud/apps/mail/lib/Account.php#700 #### Nextcloud log (data/nextcloud.log) {"reqId":"WXQpgC06PdMAAHim1aYAAAAM","level":3,"time":"2017-07-23T04:44:10+00:00","remoteAddr":"172.56.31.136","user":"circlenaut","app":"PHP","method":"POST","url":"\/apps\/mail\/accounts","message":"fsockopen(): unable to connect to mx2.zoho.com:143 (Connection timed out at \/var\/www\/nextcloud\/apps\/mail\/lib\/Service\/AutoConfig\/ConnectivityTester.php#45","userAgent":"Mozilla\/5.0 (Windows NT 10.0; WOW64; rv:54.0) Gecko\/20100101 Firefox\/54.0","version"

nextcloud / server