Monday, May 4, 2009

Citrix Protocol Driver Error

Today i faced a very complex problem. My Clients were complaining that they are are getting Citrix Protocol Driver Error. After initial troubleshooting i found that there were some http errors on my web interface servers. I restarted IIS on WIS but no luck. I restarted IMA service on Presentations servers but issue still remained same. It was strange that i am getting this error for all Applications published on different servers this means that this error is not server dependent.  i have tried Citrix article published on same issue and also tried disabling Session reliability but no luck. My Citrix environment consists of 2 Access gateway servers, 2 Web interface servers, 4 presentation servers and 1 license servers and we are using Netscaler device for load balancing. For narrowing issue i have disabled one web interface server from Load balancer and configured application to use only one presentation server but it didn’t solved the problem. I also restarted whole farm but no luck. Then i focused on Access gateway appliance and removed 1 appliance from Load balancing but issue remained same after that i enabled 1st device in Load balancing and removed second device from load balancing then after test i found that the issue is not occurring again and it is solved. I then logged on to the the troubled access gateway and found that this sever is not able to connect to the license server also this server is not configured to accept connections on port 80 only https. i am not sure why the sessions are not going to the other Access gateway which have correct configuration. I have to still fixed the licensing server connection issue but till now i haven't got any complain from the user.


Anonymous said...

Hello there,

This is a message for the webmaster/admin here at

Can I use part of the information from this post right above if I provide a link back to your site?


Khurram Ullah Khan said...

Hi Thomas,

On which site you are planning to post this content?


Anonymous said...

Thanks for the tip Khurram.... i had the same issue on load balanced citrix boxes, rebooted the suspect one and refreshed applications on the affected clients.... all logged in fine.