Recently, we got the following error while booking a resource in our schedule board. We earlier got the same error while trying to delete bookable resource booking records.

We could not figure out the workflow or SLA that could be responsible for the issue.
Eventually, turning on the Use Enhanced Background Processing (Preview) option in Field Service Settings >> Other fixed the issue for us.

Use Enhanced Background Processing (Preview)
In Field Service, a bunch of background jobs take care of things like managing Agreements. Normally, this uses the tried-and-tested workflows. However, we can flip on the new preview option that uses Power Automate Flows instead. This can help in tricky cases—like when the Agreement owner no longer has access to Dynamics 365. We could see this option enabled in our other environments, and this environment was a copy of one of them, so that could be the reason it worked in our case.
Also check –
https://community.dynamics.com/forums/thread/details/?threadid=65c9c51f-26e3-442c-bd87-4892a61b8ee4
https://community.dynamics.com/forums/thread/details/?threadid=8ceeb26f-bc7e-4a22-b2b6-672ef89c6401
Get more information
Hope it helps..
