When using Exor you might get this error message saying that it can't reserve record:
The reason behind this is that the specific record is being used by 2 or more users at the same time and the progress is not saved.
If you want quick and easy solution you can use SQL command to kill other sessions that might be causing this error message. It is not the best solution, as your colleagues work might be interupted and the changes wouldn't be saved.
The most system-harmless way would be to contact your colleagues that using the Form and ask them to click Save or finish their work in that Form.
For example (Maintenance Manager):
When one User1 is instructing a Work Order which is related to budget1/contract1 and keeps that session not saved yet and at the same time user2 is instructing Work Orders which are related to the same budget1/contract1. The message then is appearing for User2 and it disappears when the User1 has finished instructing Work Order (User1 press Save button)