The 3 lines at the bottom not working.

[TympanicFir8748]

Sometimes, I have seen people's 3 lines/recent apps button not working, this can be fixed by going to settings, then to the category "Apps" and then find One UI, force stop it and letting it start again. 

[ROCKINRALPHYBOY]

Thank you! This worked 💪 

[MindfulUK]

Wow, it worked!! Thank you 🙏

[TympanicFir8748]

Thanks for helping out the community! 😄

[lminvti]

Not a problem at all 👌