Hi Deriv Community! 
If you received the error “One or more mandatory blocks are missing from your workspace. Please add the required block(s) and then try again.” You can add the block from the Blocks menu.
You may refer to this post further for the error message above:
Mandatory Blocks
1. Trade Parameters
The Trade Parameters are important in defining the parameters of your contract for instance the market, trade type, contract type, and many more to set up your DBot.
If this block is missing, you can add it by searching for Trade parameters and drag the trade parameter block to the workspace
Or click on the set up your trade section in the Blocks menu.
2. Purchase conditions
The Purchase Conditions allow you to specify the contract type and conditions. As such, you may also search this using the search bar
Or click on the Purchase contract section in the Blocks menu and drag the block to the workspace.
3. Restart trading conditions
The Restart trading conditions block is where you can decide if your bot should continue trading. This block gets the last trade information and result, then trades again should it meet the set conditions.
You can find this by searching Restart trading conditions in the search bar
Or select the Trade again section in the Blocks menu and drag it to the workspace.
Please be reminded that we do provide the DBot on mobile via an internet browser, however, certain functions are not supported. For instance, adding blocks are not available via mobile. Therefore, for a better experience trading using the DBot platform, we recommend using your desktop to do so.
If you have any questions, please visit our Help Centre or contact us via Live Chat and WhatsApp.