What to do if the menu in the bot has disappeared?

After a long break in the use of Alice-Bob Bot, there is often a problem where the block with the menu buttons disappears. This causes difficulties in using the bot.

There are two ways to return the menu in the bot:

send the /start command to the bot's message
in the lower left corner, click on the hamburger menu and in the drop-down list, select the first command - /start