Simple RAW for 5e V: The Disadvantage Strikes Back

[E’Tallitnics]

Q19: Arcane lock says it's impossible to open a warded door while the spell is active, but the DC for picking the lock is increased by 10.
What does that mean? Can you open it with Thief Tools or not?

A19: The relevant portion or the description says, “Otherwise, it is impassable until it is broken or the spell is dispelled or suppressed.”

So not “impossible,” just “impassible until….”