Error when trying to refresh sync schema for my Dynamics 365.

I’ve experiencing error every time I want refresh sync schema for my Dynamics 365 (online ver 8.22) integration:

" Not Allowed

Error syncing schema with message: {CrmApiResponse::getSchema} Not a json for get schema: {"status":"ERROR","reason":"java.lang.RuntimeException: The entity Type can not be found in CRM

...."

The full error text is in the attachment

I’ve double-checked integration plugin versions and we have latest available for our CRM(Marketo Sales Insight ver 2.0.0.11 and Marketo Lead Management 4.0.0.21).
Synchronization itself is working fine I guess – no Notifications from Marketo system.

Can someone provide me steps to fix that problem or tell me where should I look for answer?

Thank you.