Issue Error trying to add a domain

[ZassAMC]

Trying to add a new domain using Plesk Obsidian 18.0.29, the server hangs and nothing happends.
The only error message I get is

Error: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '2' for key 'PRIMARY', query was: insert into sys_users (`id`,`serviceNodeId`,`login`,`home`,`shell`,`quota`,`account_id`) VALUES ('0','1','mich_calder','C:/Inetpub/vhosts/michelacalderaro.com','Login Disabled','0','14')<br><b>You can fix this error</b> using the `plesk repair` utility. To do so, either run the `plesk repair db` command via the CLI or <a href='https://80.211.132.153:8443/modules/repair-kit/' target='_blank'>go to Diagnose & Repair</a> and click Repair next to “Plesk Database”

This error message is returned only when using Google Chrome (not when using Microsoft Edge).
Following the suggestion in the error message, SOME of the working sites stopped working (other sites and domains still work).

Some notes that might help:
1. The new domain used to be on this server but was removed months ago (we want it back where it was now).
2. The new domain is active on another server with another I.P. address (until it has been tested with the new I.P.).
3. One of the domains on the server uses a Secure Server Certificate, and it seems to me the source of the problem.

The situation right now is that some of the sites continue to work on the server, while others are blocked.
If anyone has any idea how to approach this issue, I'd be most thankful.

Anyone who may help us for a fee, we'd be as thankful!!

One site that still works: www.endormedia.com
O site that stopped working: https://www.g6pd.org
A million thanks in advance.

 

[IgorG]

 An operation fails in Plesk: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'X' for key 'PRIMARY'

Applicable to: Plesk for Linux Plesk for Windows Symptoms When adding a customer, subscription, mail account, mailing list, IP address, changing domain hosting type or installing a Let's Encry...

support.plesk.com

 

[ZassAMC]

Many thanks for the detailed answer.
I ran the "Plesk repair db" command, which ran smoothly. However the two websites that failed continue to fail.

Runtime Error
Description: An exception occurred while processing your request. Additionally, another exception occurred while executing the custom error page for the first exception. The request has been terminated.


I'm afraid I caused some additional damage when trying to fix the original damage.
I'm not a technical Plesk expert and would love to give someone the credentials in order to fix it, or guide me how to contact an expert for pay.

Many thanks to anyone who can help us resolving this self-caused disastter.

 

[IgorG]

I'm not a technical Plesk expert and would love to give someone the credentials in order to fix it, or guide me how to contact an expert for pay.

I'd suggest you contact Plesk Support Team - How to get support directly from Plesk?

 

[ZassAMC]

Thanks a lot, Igor.
As I said yesterday, I'm a developer but not a Plesk expert.
We see that many types of support are offered by Plesk.
Could you recommend to us which type of support we have to register to in order to solve the type of problem we described in our forum post: "Error trying to add a domain"?
I know we should figure this out by ourselves but this is new to us and we're not sure about which to choose.

Sorry, and many thanks.