Hi Jānis Bojārs,
Thanks for reaching out to Microsoft Q&A.
As per microsoft, common issues for this might be improper network configuration.
Incorrect network configuration is often the cause of this behavior. Make sure the ports are properly configured. If you use a firewall or private endpoints, check these settings too. Finally, make sure the appropriate roles are granted and have not been revoked.
Can you confirm if you have added your IP address to the allowed access points in the firewall rules?
https://learn.microsoft.com/en-us/azure/synapse-analytics/security/synapse-workspace-ip-firewall
Please Upvote and Accept as answer if the reply was helpful, this will be benefitting the other community members who go through the same issue.