You seem to be using an iPhone?
Is the LTE (4G) option enabled as explained here or is the phone set to 3G only?
https://www.payetteforward.com/iphone-not-connecting-to-4g-fix/
When you do a scan for networks can you see and connect to 48 4G?
Is your APN configured correctly?
https://community.48.ie/t5/The-Knowledgebase/My-Internet-is-not-working/ta-p/45928
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