On 21.07.2021 is expected that Magneto HF (the ETH Berlin equivalent) will kick in ETC mainnet at block 13189133.
Here you can see the HF details. https://ecips.ethereumclassic.org/ECIPs/ecip-1103
Mantis is not yet compatible with the Magneto HF
- Synchronization with Mainnet and Mordor networks will be temporarily disabled
- It should be resumed approximately within a month
For assistance, please submit a ticket to the IOHK support team from the "Support" button in Mantis, or by using the submit a request form.