TypeError: Argument 1 passed to Drupal\ldap_servers\LdapBaseManager::setServer() must be an instance of Drupal\ldap_servers\Entity\Server, string given

I'm not able to reproduce this error. What Drupal version are you using?

I was just trying to preview my comment and then saved it and for some reason I created a fork?

I've poked at the code a little.

The `LdapUserManager` class extends the `LdapBaseManager` which has the following two methods:

1. `setServer()` (expects a Entity\Server object as argument)
2. `setServerById()` (expects the id of an Entity\Server object)

In the admin form there is a config value for `ldap_user.settings` called `drupalAcctProvisionServer`. This is a radio field set a string value of the server name.

This `drupalAcctProvisionServer`config value is getting loaded into BOTH of the above methods directly in many places throughout the code, and from what I can tell should be throwing errors everywhere:

In `ldap_user/ldap_user.module` it uses `SetServerById()`:
$ldap_user_manager->setServerById($config->get('drupalAcctProvisionServer'));

In `ldap_user/src/Form/LdapUserTestForm.php` it uses `SetServer()`:
$this->ldapUserManager->setServer($config['drupalAcctProvisionServer']);
This is the line of code mentioned in this issue.

In `ldap_user/src/Processor/DrupalUserProcessor.php` it loads the server this way:

$ldap_server = $this->entityTypeManager
      ->getStorage('ldap_server')
      ->load($this->config->get('drupalAcctProvisionServer'));

There are also a lot of files that setup a $server property on the class (as a strict Entity\Server object type) and then load it like this:
$server = $this->config->get('drupalAcctProvisionServer');

Hi! Can you test if this patch will work, please?

While we have this test form for backwards compatibility under /admin/config/people/ldap/user/test it hasn't received much attention and is not really recommended as a primary debugging tool (see the ample warnings on that page) and the server test page is often a better tool.

Apparently it wasn't kept up to date with schema changes and issues crept in. Combining joegl's input and larisse's patch should be sufficient now.

Please reopen if you can still reproduce this on latest dev.