For people having this issue, try the following steps:
-Changing network connections
-Clearing the cache
-Updating the app
-Reinstalling the app
-Restarting your phone
-Temporarily turning off Google Smart Lock (it helps keep your details safe and may be the reason why you can't sign in on the app.)
~if none of the above helps follow this method~
Sign into Wish on your desktop browser,
Settings>Change Password
Change your password (for those who sign in through Facebook or Google Accounts, you don't need to provide an old password, just make one.)
If you sign in using an email and password, you may choose to link in your gmail and/or Facebook account and see if signing in with either of those work.
Note: Your Facebook and Gmail accounts should use the same email address that you use for Wish.
I'm unsure about this method, but if you can't access the desktop site, try accessing Wish on your Phone's web browser or you may be able access the Wish instant app through your Gmail app on your phone and sign in from there, or change your settings. I personally haven't looked into it but theoretically, it might work.
.
If you still can't access your account, I would recommend contacting Wish via email, if they send you an automated reply, respond to it, even if it says not to.