In Bitrix24, the number of connected mailboxes depends on the pricing plan.

If you switch to a plan with a smaller number of connected mailboxes per employee, the last connected mailboxes will be automatically disabled.

All mails from the disabled mailboxes will stop coming to Bitrix24, respectively, the CRM integration will be disabled: no more activities, leads or deals, CRM contacts will be created from the mails.

If this happens, you can disable the unused mailboxes and reconnect the necessary mailbox.

Go to the CRM section - Add-ons - Webmail.

The left menu shows all mailboxes connected to your Bitrix24.

To disable an unused mailbox, go to its settings.

Click the Disable button.

To connect a new mailbox, open the left menu and select Connect new.

Synchronization folders, integration with CRM, employee accesses to the mailbox - all this will be needed to be re-configured, since the mailbox is connected as a new one, even if it was configured earlier and disabled automatically due to changes in your Bitrix24 plan.