Acrobat Pro subscription is still valid but currently can not use it and need upgrade or buy????

try @Kanikas 's link first.  only if that fails should you  proceed to these steps -

https://helpx.adobe.com/enterprise/kb/resolve-trial-and-license-expired-errors.html

if that fails, https://helpx.adobe.com/download-install/kb/adobe-license-issues-keychain-credential-mgr.html

below are solutions some users reported:

if those all fail, change your cc language. eg, try international english - https://helpx.adobe.com/creative-cloud/kb/creative-cloud-trial-mode.html

if that fails, change the install location

Hi there, 

Could you please share the message you get while trying to use the subscription? 

Do you get a trial error? Please make sure to sign in with correct ID. 

For trial error, you may try these steps: https://adobe.ly/3XNRMP9.

Hope this helps.