Hey @PiotrWikarski44780 devnet sandbox only allows you to reserve one sandbox at a time. The reserved sandbox has to fully end and teardown before you can grab a new one (whether this is the same sandbox OR a different one). Once you have clicked 'end' teardown begins (depending on which sandbox this can be 5 - 10 mins), you cannot stop this process once it had begun - this feature is not supported.
Hope this helps!
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