SMTP Email not saving password

[v84x4]

Hello

I am trying to set up my contact form
And when I send a test message it works fine

But when I try to save and then test it's getting error 535

I see that when I put my password in on the SMTP page and click save
It changes my password back to the old one

How do I fix this

I have tried clearing cache but still not saving my settings with the new SMPT password

Please help