Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Our team is looking to connect with folks who use email services provided by Plesk, or a premium service. If you'd like to be part of the discovery process and share your experiences, we invite you to complete this short screening survey. If your responses match the persona we are looking for, you'll receive a link to schedule a call at your convenience. We look forward to hearing from you!
The BIND DNS server has already been deprecated and removed from Plesk for Windows.
If a Plesk for Windows server is still using BIND, the upgrade to Plesk Obsidian 18.0.70 will be unavailable until the administrator switches the DNS server to Microsoft DNS. We strongly recommend transitioning to Microsoft DNS within the next 6 weeks, before the Plesk 18.0.70 release.
It seems you need update your Plesk up to 7.5.4 and install 2 hotfixes available from sw-soft.com
Then you can try to remove webmail from IIS and then reconfigure it with "websrvmng.exe --reconfigure-webmail" from %plesk_bin%
If this will not help then you can modify Plesk installation via add/remove programs and uninstall Horde. Then delete folder webmail from vhosts folder and reinstall Horde via add/remove programs
This is a late response but I have had exactly the same problem and here is my solution.
webmail.domain.com, gave me exactly the same error.
when I tried webmail.domain.com/imp , I have found out that everything works fine.
Then I changed the "home directory" of horde to "C:\Inetpub\vhosts\webmail\horde\IMP" (may differ in your setup)
(Start / All Programs / Administrative Tools / IIS Manager / Your Server Name / WebSites / Webmail(horde) right click / Properties / Home Directory / Local Path)
After that, I changed the "Local Path" back to the original address. ("C:\Inetpub\vhosts\webmail\horde")
Then everything was back to normal and working perfectly!
Seems like it is kinda simple confliction in registery or something like that.