Yes I Looked some threads.
[root@centos-otrs otrs]# su - otrs
-bash-4.2$ cat scripts/DBUpdate-to-5.mysql.sql | mysql -p -f -u root otrs
Enter password:
ERROR 1061 (42000) at line 4: Duplicate key name 'link_relation_list_source'
ERROR 1061 (42000) at line 5: Duplicate key name 'link_relation_list_target'
ERROR 1050 (42S01) at line 9: Table 'scheduler_task' already exists
ERROR 1050 (42S01) at line 28: Table 'scheduler_future_task' already exists
ERROR 1050 (42S01) at line 47: Table 'scheduler_recurrent_task' already exists
ERROR 1091 (42000) at line 68: Can't DROP 'text2'; check that column/key exists
ERROR 1050 (42S01) at line 72: Table 'notification_event_message' already exists
ERROR 1050 (42S01) at line 87: Table 'cloud_service_config' already exists
ERROR 1005 (HY000) at line 101: Can't create table 'otrs.#sql-731_18bf1a' (errno: 121)
ERROR 1005 (HY000) at line 102: Can't create table 'otrs.#sql-731_18bf1a' (errno: 121)
ERROR 1005 (HY000) at line 103: Can't create table 'otrs.#sql-731_18bf1a' (errno: 121)
ERROR 1005 (HY000) at line 104: Can't create table 'otrs.#sql-731_18bf1a' (errno: 121)
-bash-4.2$ bin/otrs.Console.pl Maint::Database::Check
Trying to connect to database 'DBI:mysql:database=otrs;host=127.0.0.1' with user 'otrs'...
Connection successful.
I solved the fetch problem, adding the command line on crontab with 1 minute of interval:
# crontab -u otrs -e
*/1 * * * * $HOME/bin/otrs.Console.pl Maint::PostMaster::MailAccountFetch