Dual sim cellular data keeps dropping

Hello,

I am using an iPhone 16 pro with iOS 18.21, a private Telekom physical SIM alongside my business Telekom eSIM. I am experiencing data connection interruptions every few minutes on the 5G and LTE network via the business eSIM.

• Mobile data is activated for the business eSIM (“Mobile Data Switching” is turned off).

• I have tried both APNs: internet.v6.telekom and internet.telekom.

• The “Voice & Data” mode settings (“5G Auto” / “5G On” / “LTE”) make no difference.

• Switching “Voice & Data” to LTE on the private SIM also does not resolve the issue.

The connection interruption occurs as follows:

• Both sim signal bars show 4/4.

• The data connection stalls.

• The 5G or LTE symbol disappears from the display.

• The upper signal bar (business eSIM) drops to 1/4 (the lower bar remains unchanged).

• The upper signal bar goes back to 4/4, and 5G or LTE reappears.

• The connection resumes.

This scenario repeats every few minutes.

I have already contacted Telekom support, but they were unable to identify any technical issue with the connection.

What can I do to resolve this?