The integration of credentials from password managers is only available in the Team version of Remote Desktop Manager.
Changes made to MFA handling in LastPass can force you to enter MFA credentials every time a device referencing a LastPass inegration is used.
To manage how MFA is handled when using LastPass credentials, navigate to File – Settings – Entry types – Credential management – LastPass.

Under the LastPass section, configure the preferred MFA behavior by selecting one of the following modes:
Don't trust this device: prompts for an MFA every time the LastPass entry is used.
Trust this device: prompts for an MFA only once on the current device. The trust is maintained across sessions.
Trust this device (cleared on application close): prompts for an MFA once per session on the current device. The token is cleared when the application is closed.
If multiple LastPass accounts are configured with an MFA, you will be prompted separately for each account. The number of MFA prompts may vary depending on the selected Multi-factor authentication mode.