… that your node considered block 740238 with the hash below as an invalid block,
… and upgrading your node to the most recent version (one compatible with the May 15 upgrade) hasn't solved the problem because your node STILL remembers that it considered that block to be invalid,
You should give this RPC command a go (while your node is running).
reconsiderblock 000000000000000002afc6fbd302f01f8cf4533f4b45207abc61d9f4297bf969
This will cause it to reconsider the upgrade block and should cause it to continue synchronizing with the rest of the network.
And next time, please upgrade beforehand!
If you're not running a node: This is nothing to worry about, it is expected behavior. When a node is not upgraded on time, it usually will not be able to follow the Bitcoin Cash blockchain that the upgraded network considers valid.
It will simply hang around, while receiving blocks it considers invalid unless someone extends the old rules chain (which is normally not the case unless the upgrade is contentious).