There may be a lot of reasons for the internal server error in plesk. Here in my case the situation is as follows.

FIrst of all i stopped 'psa' service and then i started again.

[root@plesk ~]# /etc/init.d/psa stop

[root@plesk ~]# /etc/init.d/psa start
Starting psa... done
Starting xinetd service... done
Starting named service... done
Starting mysqld service... done
Starting postgresql service... not installed
Starting psa-spamassassin service... done
Plesk: Starting Mail Server... already started
Starting psa... done
Starting drwebd service... failed

drwebd service failed here. Then i check the plesk service's error log and found the following entries.

====================================================
[root@plesk ~]# tail -f /var/log/sw-cp-server/error_log

2013-07-16 12:42:23: (connections.c.1737) SSL (error): 5 -1 0 Success
2013-07-16 12:42:23: (connections.c.1737) SSL (error): 5 -1 0 Success
Cannot find config item ["global/SERVERsocket==:8443", ".php", 0]
2013-07-16 12:42:24: (mod_fastcgi.c.1000) the fastcgi-backend /usr/bin/sw-engine-cgi -c /usr/local/psa/admin/conf/php.ini -d auto_prepend_file=auth.php3 -u psaadm failed to start:
2013-07-16 12:42:24: (mod_fastcgi.c.1004) child exited with status 1 /usr/bin/sw-engine-cgi -c /usr/local/psa/admin/conf/php.ini -d auto_prepend_file=auth.php3 -u psaadm
2013-07-16 12:42:24: (mod_fastcgi.c.1007) if you try do run PHP as FastCGI backend make sure you use the FastCGI enabled version.
You can find out if it is the right one by executing 'php -v' and it should display '(cgi-fcgi)' in the output, NOT (cgi) NOR (cli)
For more information check http://www.lighttpd.net/documentation/fastcgi.html#preparing-php-as-a-fastcgi-program
2013-07-16 12:42:24: (mod_fastcgi.c.1012) If this is PHP on Gentoo add fastcgi to the USE flags
2013-07-16 12:42:24: (mod_fastcgi.c.1105) [ERROR]: spawning fcgi failed.
=======================================================


Fix:

I checked the available diskspace in each disk using 'df -h' command and i found that the disk mounted /tmp directory is full and there is not enough space to create temporary files to run plesk.

I found some files as shown below using the entire space.

[root@plesk ~]# ls -la /tmp
-rw-------   1 psaadm sw-cp-server      200000 Jul 16 11:17 dumpAkwhRE.tar
-rw-------   1 psaadm sw-cp-server   4096 Jul 16 11:18 dumpY2sRjw.tar


I removed one of the 'dump' using more space and restarted the psa service again. Now the plesk service working without any error.

Change Auto-reply Limit of a Mail Account - Plesk (Windows)

Issue:

If I enable auto-reply in my Parallels Plesk Panel (PP) email settings and send a test email to that account, I get an auto-response. But, if send another test email, I do not get any autoresponse, i.e., it works only once.

There is a parameter in the "psa" database -- mail_resp.ans_freq -- that defines the daily auto-reply limit for each mailbox, and it is set to "1" by default.


Solution:


C:\>cd %plesk_bin%

To check the autoreply limit of all mail accounts in the server.

C:\Program Files (x86)\Parallels\Plesk\admin\bin>dbclient --direct-sql --sql="select concat(m.mail_name , '@' , d.name) as mailname, mn_id, r.ans_freq from mail m, domains d , mail_resp r where m.dom_id = d.id and r.mn_id = m.id;"


To set the auto reply value=10 for mail account, where mn_id=xx.

C:\Program Files (x86)\Parallels\Plesk\admin\bin>dbclient --direct-sql --sql="update mail_resp set ans_freq=10 where mn_id=xx;"

To set the auroreply value=10 for all mail accounts in the server.

C:\Program Files (x86)\Parallels\Plesk\admin\bin>dbclient --direct-sql --sql="update mail_resp set ans_freq=10;"


Note:

If you want to set the limit to zero, give ans_freq=0
If you want to set the limit to unlimited, give ans_freq=NULL

Issue:

When accessing plesk control panel using non-ssl port(8880) it is redirecting to SSL port(8443).

http://www.yourdomain.com:8880 is redirecting to https://www.yourdomain.com:8443


Solution:

Disabling SSO in Plesk (Single Sign On) will fix this issue.


The Plesk Single Sign-On service is nice for users who use several of Parallels services such as Plesk and Site Builder.

Some users may decide to disable this service due to issues it can cause if not properly configured. One of these issues is incorrect SSL certificate support for the control panel admin interface. If you are still incurring the above mentioned problem, try disabling this service with:

In Windows:

If you are using plesk in windows, login to windows server via remote desktop.
Enter the following commands in the 'cmd'

C:\>%plesk_dir%/bin/
C:\Program Files (x86)\Parallels\Plesk\bin>sso.exe --disable


In Linux:

# /usr/local/psa/bin/sso --disable


Note:

Here in this solution, both http in 8880 and https in 8443 will work. If you want to permanantly disable https in 8443, you can follow the steps shown below.


If you have Windows 2008,

Open IIS.
Expand the Sites menu.
Right click the PleskControlPanel from the site list.
Select Edit Bindings.
Remove the binding for 8443.
Click close.
Restart Plesk for the changes to take effect.

***Most of all sso must be disabled.

Plesk MySQL server have no root user. Instead Plesk have user “admin” with root privileges.

You can run the command given below to get MySQL admin user password.

[root@server ~] # cat /etc/psa/.psa.shadow
3G5wVCxDGotP4itJ


Verify the password by login to the admin user.

[root@server ~] # mysql -u admin -p3G5wVCxDGotP4itJ
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1234 to server version: 5.1

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql>




If you want login to MySQL without entering the password always, go through the following steps.

Create a file, /root/.my.cnf and add the follwong contents in it.


[mysql]
user = admin
password = 3G5wVCxDGotP4itJ

[mysqldump]
user = admin
password = 3G5wVCxDGotP4itJ


This will allow you to use mysql and mysqldump without providing passwords.

Error:

WebAdmin link for a Plesk user's MSSQL database shows 404 page not found.

Login To Plesk >> Databases >> WebAdmin show below error(Redirects to URL below):

==================================================================================================
Server Error in '/' Application.
The resource cannot be found.
Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable.  Please review the following URL and make sure that it is spelled correctly.

Requested URL: /mssql/app/connect.aspx

WebAdmin link for their MSSQL database shows 404 page not found.
==================================================================================================


Solution:

1. Firstly try to ping the sub-domain mssql.mydomain.com and check if it is working or not, if not, you need to create a dns entry for mssql. If the same error still persists, you can run the following commands in the 'cmd'.

2. Run the commands one by one in 'cmd'

   > cd %plesk_bin%

   > websrvmng.exe --reconfigure-sqladmin
   > defpackagemng.exe --fix --type=sqladminmssql

Error:

When you try to Detach a database in the MSSQL Management Studio, you may seen the following error.
When this issue happend to me, there is no issues in creating, deleting, detaching database. There is problem only in the Detaching option.

-----------------------------------------------------------------------------------------------------------------------------------------------------
C:\Program files(x86)\Parallels\Plesk\Databases\MSSQL\MSSQL.1\MSSQL\Data
Cannot access the specified path or file on the server. Verify that you have the necessary security privileges and that the path or file exists.

If you know that the service account can access a specific file, type in the full path for the file in the File Name control in the Locate dialog box.
-----------------------------------------------------------------------------------------------------------------------------------------------------

Solution:

1. Run services.msc to view all the Services in the server.

2. Find the service named "SQL Server(MSSQLSERVER 2008)".
    Check the "Log On As" column of that service, whether it is 'Local System' or 'Network System'.
    If it is 'Network System', you have to change to 'Local System', which will fix your issue. The following screenshots will give you to change it.

3. Right Click on the particular service and select 'Properties' option.

4. Select 'Log On' tab and select the option,
       Log On As:
       Local System Account
       Click on Allow service to interact with Desktop
   Then click option OK.

5. You have to restart the service to make changes in effect.
     Select General tab. You Stop and Start the service in there.
     Then click option OK.

Thanks...

1. Login to Plesk admin panel, https://<IP or domain>:8443

2. Click on 'Domains' option in 'Hosting Services'.

3. Search for the domain you want to change login password. (Let it be example.com)

4. Login to Control Panel of the selected domain.

5. Select Account >> My Profile >> General

6. You can see the account name and an option to change password in 'Panel Preferences' in 'General' tab.

7. Enter a strong password there and Click on OK button to make the changes in effect.

8. Verify user name and password using the given link, https://example.com:8443