Remove the lock for the app I installed one particular app two months ago. When I opened it the first time, a popup opened with a suggestion to enable the screen lock pin. And I enabled the screen lock. From that time whenever I opened the app it always asks for the pin. I used the app for the last two months without any problem. But from the last few days, I can't open the same application because it is showing to enter the pin even after I entered the correct pin. I thought it was a bug of that particular application and I reported it to them. They told me that the application does not asks for pin to access it. I was told to check access and security credentials in my phone, to open the apps and remove the app from the list of the apps. But I can't find any setting to check it on my phone. Could anyone tell how to check the access and security credentials to open the apps and how to remove it ?
When apps misbehave, usually clearing the cache or its data solve many issues. If the app doesn't contain important data, then try Settings -> Apps. Find it and delete its data. It should be reset as the first time you used it.

Then start it and set the settings to use it as before or change them for your new needs