WHMCS with Virtualmin Pro on Debian 8

I have two servers running Virtualmin Pro. One with Debian 7 that works with WHMCS perfectly, and the second running Debian 8 that just refuses to provision websites.

The error I get when I try to create the website from the order page in WHMCS is "Module Command Error Server Login Invalid". I have verified the username and password on the Debian 8 server repeatedly, the user is set to accept RPC calls, but no matter what I do, I get this error, and on the third attempt, the Virtualmin server locks me out and I have to go unblock the account.

I need to get this working on a Debian 8 server and start migrating off of my Debian 7 server.

Similar posts include https://forum.whmcs.com/showthread.php?109011-WHMCS-and-virtualmin-inval... and https://www.virtualmin.com/node/38777



Howdy -- hmm, it's possible that we may need to get WHMCS involved to help us troubleshoot that, but one particular thought crosses my mind... what is the password that's being used in this case?

Does it have any special characters or symbols in it?

I'm wondering if maybe they're getting corrupted during the call somehow. If there are, you may want to consider changing the password to a more simple one to see if that helps.

That's going to be a difficult issue to troubleshoot. I'm using Debian 8 and WHMCS and it's working well on my side. I know that's not very helpful, but at least it rules out Debian 8 as the broad issue.

The password I use does have a special characters in it, but as Andrychek mentioned, might be worth simplifying the password as a start. I'll gladly work through my setup with you, to help troubleshoot the issue if you like. Let me know if you're keen and we can share contact details.